AfterDark
Contributor
Biggest thing to remember, in my opinion, is not to flash the DM card on vacation, unless you are teaching. Once dive operators know you are a DM or Instructor, of whatever agency, they may ask you to "watch" inexperienced divers, which puts liability on you (I've seen it happen). Better to show them the card you need for the dive, ie you are diving nitrox and show your nitrox card, and have fun!
PS I have the MSD card, which I got just for me...
Tell em for a fee you'll watch the whole boat load. While your at it tell em you want dive free also. That should discourage em from asking twice.