Otro artículo sobre los problemas que causan los "accessibility overlays"

No es que yo busque estos artículos, ellos me encuentran a mí.

Una "web accessibility overlay" es la capa que se añade a un sitio web mediante un software que promete mejorar la accesibilidad de los sitios web.

Muchos sitios web usan los "accessibility overlays" como solución rápida para decir que un sitio web es accesible, pero no es verdad al 100%: sí que es verdad que pueden resolver ciertos problemas, pero no todos. Y el principal problema, la falta de conocimiento de los desarrolladores del sitio web no lo resuelven: los desarrollos futuros seguirán teniendo problemas de accesibilidad y existirá una dependencia de estas soluciones.

En Overlays and Plugins Aren’t the Answer to Accessibility, que incluye un podcast, explican más cosas sobre los "accessibility overlays":

Website accessibility overlays and plugins aren’t the answer to accessibility and compliance, despite being touted as an easy, automated solution for web designers and developers and their clients. They present a plethora of problems.
What Is an Accessibility Overlay 

But first, let’s talk about what an accessibility overlay is. Like some accessibility plugins, an overlay is used to detect and fix accessibility issues on a website. An accessibility overlay is installed by simply adding one or a few lines of code—javascript—to the site. It modifies the site usually only at the browser level, not touching the site’s code.
The site gets analyzed and—poof!—the site is now magically fully accessible and compliant within a day or two, and it performs regular checks and fixes to ensure ongoing compliance. Sounds great, right?
Claims Made by Accessibility Overlay Vendors 

Many of the claims made by the vendors of these accessibility overlays sound way too good to be true. Let’s take a look at some of them:

• “Just insert this code, and your site will be accessible.”

• Scanning and fixing your site will be done every 24 hours (or other timeframe).

• Overlays have a higher success rate than accessibility services.

• They provide compliance to many laws, including ADA, Section 508, EN 301549 and WCAG 2.1 AA guidelines. I noticed some touting “100% compliance,” and others said “up to 50% compliance” for x price, then “up to 95% compliance” for higher rates. What if the site ends up being in 25% compliance? Sounds like it would still be what they are promising, so your client will get screwed.

And just a side note… Ironically, a lot of these overlay vendors have accessibility issues on their own sites that are using their own overlays!
Problems With Accessibility Overlays 

Now, there are some things an automated tool can check for and fix. Industry experts estimate that about 25% to 30% of accessibility issues can be detected. Those are the more cut-and-dry issues. Some other issues may be able to be found but not fixed properly or at all.
About 70% to 75% need to be dealt with manually, reviewed by a person, not an automated tool.
So let’s get into some of the specific problems with accessibility overlays.