Criminal law, traffic matters, DUI, assault, theft, fraud
Nick unless you have been charged and banned from leaving the country, immigration will not intervene when you leave.
However if a summons is issued while you are away and you fail to respond to a court attendance you may be arrested on your arrival back. So enjoy the party and hurry back to attend to any matters that may occur in your absence.
If you end up having to go to court, instruct a solicitor to represent you in court, have him present at any police interviews beforehand.