The ADA is a horribly-designed law precisely because it encourages this behavior. Reforming it is necessary, but doing so would be so politically toxic that it will probably never happen.
Temporary event and with an accommodation solution for the minority of disabled guests shouldn't have to inconvenience everyone just because a few people "feel" inconvenciend for having to ask for the accommodation. It's not like this is a subway station, public building, or some other kind of venue where a permanent access solution is needed.
I think some people who are disabled are just miserable people who go around trying to make everyone else miserable too. That's the only reason these lawsuits are filed.