I've looked through 5 pages of archives and didn't find this discussed. In Chuck86's account of his Cozumel DCS ordeal he had some rules. #4 was to not step on a dive boat without asking if they have emergency O2 and know how to use it. My question is how many board members dive at all without O2 available? In over 300 dives (I know not many compared to some) I have not yet dove without O2 on the boat or shore and believe it would take an extraordinary circumstance before I would even though we've never needed to use it. Any thoughts?