In Canada all the restaurants have those wireless thingys & the waitress watches you as you `input’ the tip. Creepy.
Personally, I think it is more of a corporate effort to remove temptations from the wait staff to steal. It is, however, a big inconvenience to some customers, whether on principle or other reason.
Those are standard in every sit down restaurant in Norway but usually the waitron hands you the machine and walks away until you are done.