New pet peeve on tipping...

At what point did it become customary to tip the bell staff who call for a cab? I especially object to doing this at a hotel where the cabs are already lined up.

It's one thing if the bell staff has to call the cab company or give directions, but otherwise you've not earned anything.

Worst of all, they open the door and keep their palms out. I just look directly at them (so they're sure I know what they want), and then just close the door.