[tokyoxjapanxfan]

It is in fact a problem here. It's called being a chikan (if its a guy doing the molesting) or chijo (if it's a girl).

Happens on trains a lot because they get so crowded and a lot of times people don't report it.

There was a movie made called "sore demo boku wa yattenai / それでも僕はやってない" which is based on a true story about a business man falsely accused of touching a woman on a train, and instead of pleading guilty, which is much easier to do in Japan, he plead not guilty and was found guilty by the court even though he didn't do it and went to jail.

The court system in Japan is really bad. Instead of innocent until proven guilty, it's guilty until proven innocent, but yeah... Kinda off topic.