I've found I have to have a list of do not for discretion, simply because so many who also require discretion, had told me they understood discretion, didn't / don't want to be indiscrete simply were.
Very much like a few other things I have to mention because if I dont spell it out, it happens and I if I didn't see anyone who did these things, cancelled each time I would wipe out as many as 75% of punters / bookings.