Hmmm... excuse me, but I still come from the train of thought that a tip is earned, regardless of profession. It shouldn't be expected.
However, on the topic of diving, I have a few questions:
Are there regions that expect tipping for DMs? I say this as another Canadian noted that it wasn't expected up here. Perhaps some areas actually pay their DMs -- which makes sense, IMHO.
If a DM is so damned good, why isn't he being paid, with that cost then put to the consumer in the dive fee?
- ChillyWaters