The tip-taker detector is a standard penny dish which stands on scales sensitive enough to detect the weight of a note/coin accurately. The scales would be rigged up to some sort of processing unit, which would set the new value for the weight of the contents every time a new contribution is made.
The idea is to detect whenever somebody is leaving your tips (US: concessions, right?), or stealing them.

On a change in weight, the program would re-evaluate the weight. If it increased, either nothing would happen or the system would play a polite "Thank you" sound. If the weight decreased however, the program would initiate a thief-catching system.
This could be anything from locking all the doors around the dish to administering an electric shock to the thief.

Of course, some sort of failsafe would be included. A button, for example, that shopkeepers could hold down while removing tips could temporarily disable the system.
-- NickTheGreat, Oct 09 2002

Britian.Tips = US.Tips... I think. And as long as we're not talking about the 'Take a penny, leave a penny' plate. Oh, and US.Tips typically go in jars which make 'pinching' the contents more difficult.

I have to wonder if you'd ever recover the cost of the tip-saving machine in tips.
-- phoenix, Oct 09 2002


You might have an Indiana Jones wannabe trying to do the ole switcheroo with a pebble for some bills, but then you could let loose the giant rolling boulder.
-- FarmerJohn, Oct 09 2002


This is probably why the mints never get scoffed in restaurants.
-- skinflaps, Jan 05 2006


I'd like to dine where they have [giant rolling boulders].
-- normzone, Jan 05 2006



random, halfbakery