What to do when a couple embarrasses you in public?

Anyone here know a couple who go to a restaurant with you , then start arguing load enough that people around you start to look? I knew a couple that did this every time we were around them. Hell... They even had the police called to a hotel room that they were staying at because the guy was screaming in the parking lot, kicked the side of his company owned car in, then was put in hand cuffs. What do you do when you're around couple like this? They make me uncomfortable as hell to be around, and make everyone around them miserable. Just curious?
Do you just ignore it, or confront them?
Do you just ignore it, or confront them?