Is it common and ok to hav open public in japan in front of loads of ppl but no one stops or notices you?

I've seen many videos where in japan people have open on sidewalks and nobody notices them even tho its so and you can see her bouncing so hard. They do it in trains and buses too and its sometimes but no one notices or cares(some even watch) and police nvr come by. I want to do it so you think its ok bcos i want to try it out in japan.