Section 1
Why these mistakes are invisible
Accessibility barriers lose customers silently for a structural reason: the affected visitor leaves without feedback, and your analytics don't distinguish "left because they chose to" from "left because they couldn't proceed." A blind visitor whose screen reader can't navigate your booking form doesn't appear in your data as "blocked by inaccessible form", just as a bounce or an abandoned session, indistinguishable from any other. So unlike a broken checkout that generates complaints, accessibility barriers degrade your results without revealing the cause, which is exactly why they persist: you can't fix what you can't see. The remedy is to find the barriers proactively (through testing) rather than waiting for feedback that never comes. The principle: accessibility barriers lose customers invisibly, affected visitors leave without feedback and analytics can't show the cause, so the barriers must be found proactively. (This applies the accessibility research cited across this library.) A broken checkout gets you angry emails. An inaccessible form gets you silence, the visitor who couldn't use it just leaves, and your analytics record an ordinary bounce. That's what makes accessibility mistakes so expensive: they cost you customers without ever telling you they did. You don't have a feedback problem; you have a visibility problem.
Section 2
The common mistakes (and how to catch them)
1, Poor color contrast. Low-contrast text (failing WCAG contrast) is unreadable for low-vision users and hard for everyone in bright light. Catch it: a contrast checker on your text/background combinations. 2, Images without alt text. Missing alternative text means screen-reader users (and AI) can't understand your images. Catch it: audit images for meaningful alt text. 3, Forms that aren't accessible. Unlabeled fields, keyboard traps, and inaccessible error messages block users from completing your most important conversion action. Catch it: navigate your forms by keyboard and screen reader; this is the highest-stakes area to test. 4, Keyboard-inaccessible navigation/interactions. If a visitor can't operate your menus, buttons, or interactions by keyboard, many assistive-tech users are blocked. Catch it: try to use your whole site with the keyboard alone. 5, Missing structure (headings, labels). Without proper heading structure and labels, screen-reader users can't navigate or understand your page. Catch it: check your heading hierarchy and labeling. 6, Video without captions. Uncaptioned video excludes deaf/HoH users and the muted-autoplay majority. Catch it: ensure captions on meaningful video. The cross-cutting fix: test, by checker, by keyboard, by screen reader, and ideally with real assistive-tech users, because these barriers won't surface through complaints. And avoid overlay widgets as a shortcut; they don't reliably fix these and have drawn lawsuits. (These are the commonly cited barriers from the accessibility research.)
Section 3
The silent-loss mistakes, in one view
The takeaway: accessibility mistakes lose you customers silently, affected visitors leave without feedback, and your analytics can't show the cause, which is exactly why the common barriers persist. Poor contrast, missing alt text, inaccessible forms, keyboard-inaccessible interactions, missing structure, and uncaptioned video each quietly turn away visitors who could have been customers, including but not limited to the one-in-four adults with a disability (1). Because these barriers won't surface through complaints, you have to find them proactively, by contrast checker, keyboard navigation, screen-reader testing, and ideally real assistive-tech users, and fix them properly rather than reaching for an overlay shortcut. You can't fix what you can't see, and accessibility barriers are designed, by their nature, to stay invisible until you go looking. (The lost-customer framing synthesizes the accessibility research established across this library.)
Section 4
Execute This With AI
Step 1, Inputs. Note your site's key pages and conversion actions (especially forms), and any known accessibility issues. Step 2, Run the prompt: You are an accessibility auditor focused on the mistakes that SILENTLY lose customers (affected visitors leave without feedback; analytics can't show the cause). Common barriers: poor contrast, missing alt text, inaccessible forms, keyboard-inaccessible UI, missing structure/labels, uncaptioned video. They must be found proactively (checker, keyboard, screen reader), not via complaints. Avoid overlay shortcuts. My key pages + conversion actions (esp. forms): [DESCRIBE]. Known issues: [LIST]. Do four things: 1. Give me a prioritized checklist to test for these common barriers (forms first). 2. Tell me exactly how to test each (contrast checker, keyboard-only, screen reader). 3. Flag where on my site these barriers most likely cost me customers. 4. Tell me the one fix likely to recover the most silently-lost visitors. Help me find the invisible barriers, then fix them properly. Step 3, The keyboard test. Try to complete your most important conversion action (e.g., your contact/booking form) using only the keyboard, "can I do it? If not, neither can many of my visitors, silently." Tools and expected output. Any frontier chat model, plus a contrast checker and your keyboard/screen reader. Expect a prioritized test checklist, how-to-test guidance, likely-cost flags, and the top fix. The QA discipline: these barriers are invisible in analytics, so they must be found by real testing, checker, keyboard, screen reader, ideally assistive-tech users, not assumed absent because no one complained. Overlay widgets don't reliably fix them. This is general guidance, not legal advice. The model builds the checklist; real testing finds the actual barriers. Accessibility mistakes lose you customers silently, affected visitors leave without feedback, and your analytics record an ordinary bounce, not "blocked by an inaccessible form." That invisibility is exactly why the common barriers persist: poor contrast, missing alt text, inaccessible forms, keyboard-inaccessible interactions, missing structure, and uncaptioned video each quietly turn away potential customers. Because they won't surface through complaints, find them proactively, by contrast checker, keyboard navigation, screen-reader testing, and real assistive-tech users, and fix them properly, not with an overlay shortcut. You can't fix what you can't see, and accessibility barriers stay invisible until you go looking. Going looking is the whole job.
Section 5
Keep reading
Keep reading in the Accessibility & the EAA cluster and across the library: [The Business Case for Accessibility (Beyond Compliance)](/blog/the-business-case-for-accessibility-beyond-compliance), [Designing for the 1 in 4: The Market Your Website Is Probably Excluding](/blog/designing-for-the-1-in-4-the-market-your-website-is-probably-excluding), [Accessible Forms: Designing Lead Capture Everyone Can Complete](/blog/accessible-forms-designing-lead-capture-everyone-can-complete). Also relevant: [The Motion Accessibility Mistake That Excludes Real Customers](/blog/the-motion-accessibility-mistake-that-excludes-real-customers), [The Service-Business Website Priority Stack: What to Fix First When Everything Needs Work](/blog/the-service-business-website-priority-stack-what-to-fix-first-when-everything-needs-work), [The Web Design Mistakes That Quietly Cost Service Businesses Clients](/blog/web-design-mistakes-that-quietly-cost-service-businesses-clients).