Say I have some files on remote A. But I'm away from it, and transferring
files from B to C. I'd like to avoid transferring any files I already have
on A. 

Something like:

	git annex copy --to C --exclude-on A

This would not contact A, just use its cached location log info.

I suppose I might also sometime want to only act on files that are
thought/known to be on A.

	git annex drop --only-on A

--[[Joey]] 

[[done]]
