Rules is rules and if you break them then you must be spoken to, if it was a legitimate mistake then a simple warning should suffice , but if the offender is to continue then they must be banned, i have personally made mistakes and been scolded for my actions, these were simple mistakes and i have been warned, but, like i say rules are rules and if continued to break them then a punishment is due!!
Were only human after all we all make mistakes but the ones who do it on purpose then that is a different matter, we can all spot a trouble maker and the tell tale signs are all ways there, 1-2-3 strikes your out = ban,
This is just my personal opinion.