Before attending the Standards.Next event on Cognition and Accessibility, I would have agreed with Nathanael and Andrew, but listening to two of the speakers who had recently done usability testing effectively changed my mind.
In her presentation on Accessibility beyond code, Antonia Hyde presented video footage of some very interesting usability tests. One of her conclusions was that "Alternative ways to access content like text size or colour scheme can make or break a site."
In Cognitive accessibility testing, David Owens came to a similar conclusion. I think it's worth quoting him at length because he directly addressed my point of view up to that point.
The next thing which I want to talk
about is related, in that it is also
an example of idealism, or dogma,
versus pragmatism. For a long time I
had taken the view that educating
people about how to use their browser
was the best way to make the web more
accessible. A key example of this is
text-resize widgets.
I was sat down with Richard, who has a
mild learning difficulty, and I asked
him if there was anything he could
think of that would make it easier to
use the website.
The first thing he said was "I wish
there was a way to make the text
bigger".
I replied, "Well you can do that the
same way you do it for any website",
knowing that all our fonts were set up
nicely, and that we had zoomed in on
every page we built at the design
stage.
Richard explained that he had been
told how to do that lots of times
before, but that it was difficult to
remember. There were so many menus and
short cuts to learn that he had simply
given up trying.
When put that simply, the case for
presenting that option up-front seems
pretty solid. Of course there are all
kinds of browser settings that could,
or should, be easier to get at, but
for something as simple as a
text-resizer it seems a no-brainer.