Review flagged the 'access not allowed' substring:
if tmux's denial text drifts while keeping exit 0, unauthorized
connections would classify as ok and the false-joined status/leave
misreporting would silently return. A clean authorized list-clients
writes nothing to stderr (verified 3.3a/3.5a/3.6-SunOS, incl. invited
read-only clients), so rc 0 plus any stderr output now classifies as
unauthorized: no message text consulted. Drift in any direction
degrades to a hidden party, never to a false ok.
veg
938491df1e