Replying to My campus PD

Howdy,

So a few weeks ago we hit an urban spot on campus, I posted some of the pics from the session on my Facebook page. We got in and out no interaction with any police or campus PD of the sort. We even talked to a janitor who came out and watched for a bit, told us to be careful and returned.

Today my girlfriend was contacted via campus PD that they had seen on my Facebook that she was dating me, and that she should tell me I shouldn't do that again or I would be charged with criminal trespass but for now all was good,

I don't mind being told to leave a spot, there was no no skateboarding signs or anything of the sort (although I do realize urban isn't smiled upon) but nevertheless never was told by them.

What offended me was them contacting my girlfriend WITHOUT ever contacting me, essentially trying to embarrass there way into getting me never to hit urban there again without ever opening or attempting to open a conversation with me.

I know there was no harm, but is there anything I can or should do? It bothered me how they went about it, I know it's unprofessional on there behalf, but I have no idea if there was anything legally or logistically wrong which they did.

Amateur lawyers of NS help