Being 100% honest. I just have no fucking clue what I can and cannot enforce. If I decide 'Hey stop doing this silly behavior' there's a 50/50 shot I get reported/into a lengthy argument with the player about roleplay or another staff member who outranks me tells me to drop it and stop bothering the aforementioned player.
These are in the few instances where I think I have a case. Otherwise I stare helplessly as marines do bizarre stuff and I think 'Well I could feasibly see privates doing this but I really think it's starting to cross a line' but I can't say anything because I know someone's gonna start shit over it and I don't have any clear cut rules to back me up so I just avoid the headache. Mods unironically have so little authority to enforce roleplay at their discretion that we're petrified to do so. We're the lowest ranking staff and even as an Smod I have no more authority than a regular mod if there's an admin on because I have to defer to them in the few instances I would get to exercise some autonomy.
People can say stuff like 'reasonable character' and that gives me a vague idea of who I can smack but it's not anything concrete and it's not that it doesn't let us identify people who are being issues but it doesn't give us any solid backing if there's pushback to our decision or disagreement from other staff present, because if they see you bwoinking and noting and banning for RP issues they don't see as an issue you better believe it's gonna start a discussion that's just not worth the headache.