They may be put into groups of three by the teachers, so the other two boys he does it with may not be friends at all; although, that said, it does sound more like the sort of school where they would choose their own groups.
But I can totally see two teenage boys being willing to do it in a way that would be designed to wind up the teachers just for the hell of it. As Pennington certainly would.
I like that Nicola has this effect on Patrick - Ginty would never have suggested such a thing. Patrick has to be braver and a better person being friends with Nicola. (I want to say, maybe that's part of the reason he dropped her, but trying not to wind up the Patrick likers...)