No, they say "we'd like to offer you a nightcap or coffee in our bar."

I wonder how much of the variation can be explained by restaurant policies regarding the booking and timing of reservations. In good French restaurants, the tradition is that you "own" the table for the evening; they don't do two dinner sittings. Elsewhere, there may be early and late or staggered reservation times even in very expensive restaurants, so that there's pressure to turn tables on time.

I've been told that in Germany, if you ask to pay three times but nothing happens, you're entitled to leave without paying. Usually standing, putting coats on, and starting to move toward the door will bring the waiter/waitress running with the bill.

I too downgrade the tip when the waiter/waitress or bus person removes dinner plates while someone is still eating the main course or presents the dessert menu prematurely. I've checked with professionals who evaluate top restaurants and the rule is supposed to be that all dishes from a course are cleared at the same time from a table. [At a banquet or large function, this would be partly based on when the key person finished eating, sort of like the etiquette of not leaving before royalty or the President.]