Banned from Japan for punching a police officer. That doesn't surprise me. I was witness to an incident in a bar (argument over an expensive bar tab) where one guy tussled with the bar manager and literally scratched him, maybe drawing a bit of blood. He was arrested and taken to court, and had to pay something like Y200/300,000 as apology money, and his legal fees were about Y2 million IIRC.
I heard of another incident where a guy was arrested after an assault on a karaoke bar manager. He was detained for 6 months while they were preparing the case for court, during which time he obviously couldn't work. Eventually the case was thrown out due to a discrepancy in the evidence.
Moral of the stories: don't lay a FINGER on anyone when you're in Japan. The travel advice for Japan from the British Foreign Office used to warn about Brits getting arrested after fights over expensive bar tabs.