Mick,
If you're using GetPoint off the Editor, it wraps acedGetPoint, which DEFINATELY returns points in the current UCS.
Kerry,
As far as passing the objectId or a reference to an entity, the reference would be preferable in my opinion.
If you pass the reference, it AT LEAST has to be open for read and you can check this, whereas passing an objectid,
you would then have to open it up thru a transaction to do your mojo....does that make sense?

?
If you've got a reference to an entity, pass it - it's easier imo.
Cheers,
Glenn.