Well, that tells her a lot about many things. Like maybe he was not a stranger to visiting the Astronomy tower with some paramours?

Shit, did I really just think in terms of paramours? Am I fifty?

She shakes her head, distracted. "It should be - and in any case, it does no harm. I mean, I don't think it does any harm, as long as it's character building type of rule-breaking. Like clandestine snogging, or other normal things for teenagers to do."

The implied thing here is not that we'd know.