As long as it is not a large enough percentage of drivers to significantly affect the service times of those riders, does it actually matter? I mean, morally I don't think they should. However, those are probably more likely to be the people who were going to cause problems like this article talks about anyways. So it would still probably result in better experience for everyone.

If 99% of drivers check that box, and it affects service times, then they will have to come up with some other option to accommodate the drivers. Prove the allergies or something, since some of them are certainly lying with prevalence being 10-20% in the US. And it would have to be a best effort, the rider with a true service animal is legally protected and a driver with allergies or fear is not a legal reason to reject service altogether.

Seems like that is pretty easy to deal with by simply asserting in the driver's contract that they can be asked for medical verification at any time if they make that indication.

What does that look like? Force drivers to go to the doctor (even though you don't give them health insurance) to get a note that says "I sneeze around dogs"?

Uber could/should pay drivers who pick up service animals more to counterbalance.