A beer company in Italy has created a heat-activated coaster-sized sticker that fits in urinals for men. If they pass more than a pint’s worth of liquid the sticker reveals a message that says they should call a cab.

…after 25 seconds of pee – a length of time at the urinal that would only occur if the person relieving themself had drunk more than one pint of beer (the Italian drink-drive limit).

I am sure bars also like it because it reduces the cost of cleaning the men’s toilets.