Default CSS question

[Justin]

I was looking at the colorblind filters on http://colorfilter.wickline.org/ 
  .

They also have a few other filters that test the ability to change the  
colours on the page (these are the coverage tests).

The idea is that if you have specified a default colour for an  
element, the filter will be able to change it. To pass the test either  
all of the colours should be changed to the same colour, or the page  
should be displayed as normal.

The reasoning is that if only a few of the colours are set, they may  
be unreadable with some user's/browser's defaults.

I have tested the pages on the build.fluidproject.org site and have  
found that some of them pass and some don't.

I'm wondering what others think of this sort of test.

It is explained in more detail here: http://colorfilter.wickline.org/faq/

Thanks
Justin