Because most guests have a smartphone and tablets today, we only provide one public computer. In most case it's very enough but a very few guests tend to occupy the public laptop for ridicously long hours (5 hours+) and disturbs everyone.
When that guy is told that someone else is waiting, he will let others use it but he'll also stand right next there to wait to grab back "his' laptop. It makes other guests feel uncomfortable.
To charge for the use is a very last resort because we don't like the idea of charging a penny for such a small service. We just want a fair use.
I am looking for a simple screensaver software and people need to input a randomly generated password every 30 minutes after their use. Any advise is appreciated.