Originally Posted by
thegoderic
On the other hand, there's nothing to say how big a glass of wine (or, when Grosvenor House were charging for dinks, a glass of Laphroaig) should be.
I always pay, but sometimes my hand slips when pouring.
This is the answer. Always have the courtesy and honesty to fill out the slip and include every glass, but the pour is as generous as you desire.