can't unadd an empty dir by rm'ing it

Trying to unadd a dir by 'rm' errors out:

% $svn mkdir foo
A         foo
% $svn rm foo
subversion/svn/delete-cmd.c:92: (apr_err=195006)
subversion/svn/util.c:913: (apr_err=195006)
subversion/svn/util.c:908: (apr_err=195006)
svn: E195006: Use --force to override this restriction (local modifications may
be lost)
subversion/libsvn_client/delete.c:472: (apr_err=195006)
subversion/libsvn_client/delete.c:366: (apr_err=195006)
subversion/libsvn_client/delete.c:366: (apr_err=195006)
subversion/libsvn_client/status.c:501: (apr_err=195006)
subversion/libsvn_client/status.c:501: (apr_err=195006)
subversion/libsvn_wc/status.c:2655: (apr_err=195006)
subversion/libsvn_wc/status.c:2655: (apr_err=195006)
subversion/libsvn_wc/status.c:1350: (apr_err=195006)
subversion/libsvn_client/delete.c:75: (apr_err=195006)
subversion/libsvn_client/delete.c:75: (apr_err=195006)
svn: E195006: '/tmp/svn/wc1/trunk/foo' has local modifications -- commit or
revert them first
zsh: exit 1     $SVN rm foo

Removing the dir with --force works.  But it should work without --force too (as
the dir doesn't have any properties or children or copyfrom).