I've heard people who are groped on trains in Japan hardly ever do anything to stop it when it's happening to prevent unnecessary conflict. If that's true, I couldn't resist touching beautiful Japanese women on my way to work.
What you seen in ero games or hentai are fiction and mostly exagerated. In reality if you get caught as a "chikan" you can go to jail by the law. If the victim or people around her took a picture of you and post it on a BBS, your public image will be ruined really fast. Most companies wouldn't hire you at all if you have criminal record. The worst one if you touch the "wrong" girl, they can scam and blackmail you back.