I almost never see anyone in the handicapped seats let alone a wheelchair. The theater I usually go to has some unmarked seats in the same row, and it’s a good spot if you don’t mind being a bit closer to the screen. (And you don’t have to climb over people if nature calls.) Although I sometimes worry someone in the elevated row just behind is going to put their feet up on the railing, and get shoeprints on my head. 😉
Older theaters I recall always had handicapped areas way in the back.