Cleanup after removing svn:external entry?

Hi,

I was wondering if there is a reason why SVN (commandline client/libs/etc)
doesn't automatically clean up after getting an update removing the
svn:external property or part thereof? ie:

r1 has svn:external = "common some_path_to_repo"
r2 removes svn:external
when I co r1 I get a new directory "common" also checked out
when I update to r2, "common" still exists

Just curious. :)

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