Parts Glass
A cup of hot glass, eh Is this a strange request, or something quite common in some parts?

Do some customers apparently as a hot glass as part of a B & B or French Connection, and how? Is this weird or not? Are these the only drinks that are heated in this way? Are you the warmth of the brandy, or just the glass? No heat to break the alcohol? In the freezing of gin will break, so what? How to heat a cup for them without having to search everywhere and ashamed in front of everyone?

This is normal. Drink a glass of hot brandy by night is something of a tradition of old-fashioned "here, in most social circles in the U.S., but certainly still exists. The heat can cause that parts of the beverage to evaporate faster, but not enough to radically change the constitution of brandy.