tag namespace?

Hi List,
local and remote git branches live in different namespaces
refs/heads/* and refs/remotes/* respectively. thus, fetching from
remote repo never collides with local branches. Unfortunately, tags do
not enjoy such a separation. When I use
       git read-tree -prefix=libfoo/ -u remotes/foo/master
remote tags suddenly populate my local tag space.  v1.0 comes from my
project while v1.1 comes from foo.

When using subtree merges is it possible to create a "remotes"
namespace for tags?
Something like --tagprefix option for git-read-tree or any better solution?

--Leo--