Re: on-page controls considered bad practice?

Tobias,
The websites that most often do this, and which probably number among the
ones you've seen, are the websites that are running a so-called
"accessibility overlay". For a monthly payment by the website owner these
overlays claim to do two things: a) provide web users with a whole list of
accessibility customisation facilities, and b) make the website
accessibility and/or WCAG compliant and, in the US, protect them from being
sued under the US ADA. Websites using them are easily recognised because
they are required to show an "accessibility" icon button on their home
page, to open the menu of custom facilities you speak of.

For (a), as you quite rightly say, the same facilities are already provided
by the browser or the operating system or both. Not only that, but since
the users are already using the internet and in most cases have been doing
so for a long time, they will already have chosen these browser settings
long ago for all the other web surfing they do! The overlays are just
charging naive but innocent businesses for something that is already
available universally and free of charge.

The far more serious side of it though is (b), and this is what makes these
overlays a fraudulent scam that the law in all countries ought to clamp
down on. The claim to make a website magically WCAG compliant by adding a
chunk of JavaScript is completely false. It is not possible for computer
software to do that, because WCAG and accessibility compliance is far too
complex for any piece of software to achieve using automated tools. Witness
the long involved discussions in this forum, in the WebAIM forum, and
others - we can't even agree amongst ourselves what is WCAG compliant half
the time, so no bit of software is going to be able to come along and do it!

I wouldn't waste your time complaining to the overlay makers as they are
just in it to make a mint of money. They don't care and will go on selling
their product as long as unwitting website owners continue paying them. But
warning a website owner, that is using one of these things, that they are
wasting their hard earned money (and in the US, risking a hugely expensive
lawsuit or legal challenge into the bargain), is a good thing to do.