Not too sure what kind of slings you guys are using that they get in the way or bump anything but I always have mine on.
Scope is always on 3 unless it is a fixed 4, I do take the quiver off of my Bow though, mainly because I don't want to knock any arras out by hitting them on the stand, tree or brush if I have to twist for a shot.
Gun is also unloaded before any climbing is done....that has bit me more than once though, forgetting to chamber a round after making the climb.