While bowling the state tournament yesterday, one guy on the adjoining lane would bowl his first ball, and then stand on the back of the lane, waiting for his ball to return and for me to bowl. I never asked him to step off the lane, but I waited for him to go ahead and bowl his second ball before bowling. His teammates never said anything to him, although I know several of them and they know better.
Also, some people in league will step up to the lane beside you, waiting for you to bowl, and practice their armswing while waiting. My peripheral vision is probably better than many, and I can see this motion beside me. It is distracting. I normally step off the lane and allow the person to bowl.
How would you handle each of these situations.