Yes. I often have a Glock in my backpack, one of the thousands of reasons I do not travel to communist occupied zones like NYC.
So I guess you think it's unreasonable that someone might explode a backpack full of explosives in a subway car?
I think this is likely to happen with or without random searches. We could likely stop numerous vicious crimes with warrantless weekly searches of homes but we don't and we shouldn't.
So drive to New York. The good guys could use the extra firepower.