Based on what I've read, you get some sort of "invoice" for the cost of dealing with you.
The legalities of whether the invoice is enforceable or not are disputed.
They are quite within their rights to report it to the police, but I think other than an invoice as mentioned above, nothing will happen.
As for being banned, well, I wouldn't go back to the original one, but I doubt you'll have a problem in others. You will technically be a trespasser, but as trespass isn't a criminal offence (except for things like railways etc), all they can do is ask you to leave. They can't claim compensation via the civil method, as they won't have suffered a loss by you trespassing.