If everybody gets extension, say a 2 hr test becomes 3 hrs, then eventually there will be someone who claims 3 hrs is the new normal time and still demand an extension over that.

It really depends on the perception of whether the goal of the extension is to give disabled students an edge over "normal" students or to give everyone a fair(not necessarily equal) opportunity to complete the test.

That's a great question, actually. Timing tests appears to arbitrarily punish students.

Doesn't satisfy the ADA. Department of Ed will sue and say that an accomodation given to everybody is no accomodation at all.

So it's not really an accommodation that's required by the ADA, but an advantage over the baseline?

Are you implying that if someone walks up a wheelchair ramp, then the building is violating the ADA?

No, of course not, that'd be ridiculous. Where did you see that in my post?

To explain in more detail. The ADA says that an accommodation is when an entity (business, employer, school) makes a change of behavior. Installing a wheelchair ramp in an older inaccessible building is an accomodation. Granting extra time is an accomodation. Simply having accessible buildings or excessive time is not an accomodation.

But why the lawyers treat it differently. Business feel comfortable, when they have a ramp, arguing that no accommodation is necessary for the wheelchair bound. The standards of accessible physical design are clear. Schools do not feel comfortable saying that no accommodation is necessary for mental health issues, ever. Their lawyers advise them that it's much better to give some sort of accomodation and argue in court about sufficient accomodations vs giving no accomodation at all.