It's not that you can't, you shouldn't
Just because someone isn't supposed to do something, doesn't mean they won't. A lesson in fisticuffs and football coaches.
There is a difference between can’t and shouldn’t. That difference has become blurred in part because of the way people speak on the internet these days.
I’ll start with an example. After Oregon State defeated Oregon in Saturday’s Civil War, the Beavers fans were on the field. One made a hand gesture toward one of the Duck players and appeared to say something. The Duck player ended up hitting him in the back of the head.
Several people who responded to this incident by saying, “He can’t do that.”
This is blatantly incorrect.