I doubt he had the kids along, parents are people too, and deserve a chance to let their hair down. Yeah, you hope you don't wind up in the lock-up, but if he wasn't playing you wouldn't begrudge him a drink with his wife.
It also means you get locked up just for being pissed, rather than for being pissed and angry, because nobody can handle your size and it's safer to let you sleep it off on the slab.
Source: Personal experience (I'm 6'4" and was a bit of a drinker in my youth).
I'm 5'9'' and at the Bathurst motorcycle races was put in the slammer for having a leak in a bunch of trees but the police must have thought I may offend the Hells Angels and their friends so I saw the inside of a divvie van. They picked up a guy who was asleep next to the only toilets on site for being drunk and disorderly (maybe he should have crossed his legs?). He could have been Brian and his wife I suppose.