I've never seen a moorings boat with the holding tanks zip tied.

Evan - they aren't guests.. they are crew <img src="http://www.traveltalkonline.com/forums/images/graemlins/Wink.gif" alt="" /> I think as long as the person opening/closing knows what to do, that it shouldn't be a problem having someone else do it. Just make sure everyone knows where it is..

The charter we just did with Beerman, he thought the port side had two tanks.. each time he was opening and closing two vales. No harm done as the valve that was NOT a holding tank was just another exhaust for the generator that went under the hull - I noticed it as I was coming back to the boat one time in the dinghy with the generator running and I saw no water coming out.. Thought we had an issue, but I eventually figured it out.