At least in Germany in restaurants glasses have to have a "Füllstrich" for this reason: > https://de.wikipedia.org/wiki/F%C3%BCllstrich https://de.wikipedia.or

At least in Germany in restaurants glasses have to have a "Füllstrich" for this reason: > https://de.wikipedia.org/wiki/F%C3%BCllstrich https://de.wikipedia.org/wiki/F%C3%BCllstrich The "Füllstrich" is a small line at the glass with a number next to it with which you can easily check whether you got the claimed amount.