My only experience with this is that because "EliteAccess" people rush on-board prior to F passengers, I've noticed the FA's waiting until a decent amount of F passengers have boarded for pre-departure drinks. (Otherwise the FA's get stuck in the aisle as coach passengers move through.) On a few flights, because F passengers weren't able to board until right before departure, pre-departure drinks weren't offered.

However, those exceptions excluded, I've experience no change in drink service before and during flight time.