-x option inoperative with "bind" mounts

[Louis-David Mitterrand]

Hello,

I have this mount defined in /etc/fstab:

/backup/current/usr/local/share/premier /var/www/g5/trunk/Naxos none bind,ro

When I backup /var with rsync using (among other) the -x option (one
filesystem) then the whole contents of
/backup/current/usr/local/share/premier are also backed up as they are
mounted on /var/www/g5/trunk/Naxos.

Is this expected behavior? I thought -x would exclude any mount,
including "bind" mounts.

Thanks,

-- 
"Faith strikes me as intellectual laziness." -- Robert A. Heinlein