The goal is to get someone to go do something else for a little while so that their body and/or mind can realize that it is tired, not to create an oppositional relationship where you tell them "big brother says don't play games". That kind of oppositional relationship is only likely to make someone resentful of the restriction. Just getting up and moving a bit can make a big difference. I'm not trying to tell someone what behavior is virtuous - I just don't want to help kill them.