In reply to Howard J:
It has been really interesting seeing the different ethics on overtaking and belay sharing depending on nationality.
On my first trip to El Potrero Chico in Mexico (an area replete with Americans and Canadians) my buddy and I decided to simul climb a multipitch route. I think it was about 10 pitches, and well within our onsight ability. We were on a bit of a tight schedule since he had to start work later that afternoon, hence the choice for a rapid simul ascent.
Anyway, there was an American couple already on it, about half way up. We climbed six pitches in the time it took them to climb one. They were at a massive belay ledge. The anchors were brand new, massive bolts, connected with a chain and ring. We just assumed it would be fine to pass, giving the cursory "mind if I nip past you here, won't be a minute". It did not go down well. They were extremely upset and outright refused to let us go anywhere near their belay ledge, let alone pass. They said that we should have woken up earlier, and that we were ruining their day. We decided not to escalate further and we rapped off once they had cleared the stance.
I'm now in Squamish and it seems to be a similar story. The team that is first on the route effectively "own" the route. You need to ask permission to go past someone, and there is a good chance they will say no. I do wonder what their reactions would be if they tried climbing in the alps! I've had French and Italian guides literally climb over me at belay stances before.