In reply to Trangia:
>
> I don't think you can lump sport and trad into the same scenario. In trad once the leader has shouted "safe" he/she should be belayed to the stance and independent of any belay protection by from the second.
Most of the people I climb with shout 'safe' when they at the top of the crag (single-pitch) but before they have belayed. Not the 'modern' way of doing things, but we all tend work on the principle that we are unlikely to fall off the top of the cliff.
Multi-pitch, you keep them on until they let you know they are attached. If in doubt, pay out a metre of slack and put an overhand knot in it - you can both get on with stuff, but they are still belayed.
In sport we would never take the leader off (why would you?), unless it was multi-pitch and it was clear they had belayed.
Chris