[al_borland]

> In some breweries and countries, the beer mat placed on the glass signals to the waiter that the guest does not want to drink any more beer.

Interesting. I’ve always seen this as a signal that a person was stepping away, but coming back. The person would cover it while going to the bathroom, in part so it isn’t as trivial for someone to slip something in their drink. Implying that they intend to keep drinking it once they return.

I’d be interested to know where it means that the guest doesn’t want any more beer.

[gnatolf]

All over Germany, and it's been around much much longer than the fear of having something slipped in your drink.