They weren't fighting locals, they were just letting off steam, like sailors have done for centuries. I like the bit about "once they pick up their teeth off the ground they are best friends", and out of a crew of around 800 there were six arrests? Not a serious problem by anyone's reckoning really. Britain is a 'pub culture' (there's a pub onboard the Carrier!), the legal age for drinking is 18 and we all start a lot younger than that (to build up a tolerance!) and our beer is STRONG! Well a lot of it is German or Scandinavian and they know how to make good beer! American Beer by contrast is known worldwide as being like 'making love in a canoe' (It's F***ing close to water, as the Aussies say!)(we have a lot of Aussie beers here too)(please excuse all these brackets), so we have potential for a small culture clash there.
As for tipping, in most countries outside the US, waiting staff are paid a fair wage to start with and don't rely on tips to make it up to a living level, so the tip is really just a thank you for good service rather than 'your boss is a tightwad and here's some cash so you can eat this week'. In Scandinavian countries if you leave a tip for the waiter they tend to give it back as they think you assume they aren't being paid. It's a bit insulting to them actually. I suspect nobody briefed the sailors on the rules of tipping before they went on shore leave. Simple misunderstanding, after all there's a lot of youngsters in the crew who've never been abroad (apart from Spain) before.