i mean police never needed pc to engage someone in a conversation.
to actually detain someone they need reasonable suspicion, not probable cause.
"hey can i talk to you for a moment about x, y, and z" -requires neither pc nor rs
"i am detaining you in relation to x, y, and z" -requires rs
the difference here being voluntary vs nonvoluntary. police are absolutely going to ask questions from people, it's up to the person being questioned to y'know, walk away or otherwise disengage from the conversation.
i'm sure that there will inevitably be someone roleplaying a cop that's abusive, but that's something that will have to be most likely have to be addressed in rp, like going through their supervisor or the courts. will we see rules? not likely, unless it's super exploitive (funneling police gear from armory), beyond excessive, or infringes on other rules through their actions (racist, mass rdming, powergaming)