It has nothing to do with being paranoid. I have used a wheelchair since 1988. They could and would be the perfect way to smuggle explosives or anything else. Especially considering that many people would go out of their way to give a person using one a pass out of political correctness.
...and especially after a young man at OSU with connections to a mosque blew himself up outside the stadium during a game. He had been refused entry by a security guard.