MDW - 4/19/2012 1:19 PM 
Thanks for the quotation. I think this is the first time anyone found my words valuable enough to repeat (or at least the first I’ve actually seen it happen).
I’d also like to add that when one of your buddies pukes in her regulator (twice), it’s time to call the dive (duh). Moreover, if you are the one who is sick, please thumb the dive. This weekend, this actually happened, and after the first spew, the ill diver signalled "I" (points at self) "am going to surface now" (points to surface). I would have preferred a "dive is over, all three of us are exiting right now" (thumb up). Luckily nothing bad happened, but we didn’t even know about the vomit until we were all on dry land. The moral is: communicate, communicate effectively, and don’t be afraid to end the dive for everyone if you are starting to get in a situation that could get very bad very quickly. Being overly considerate of your dive buddy’s desire to complete the dive could be putting your life at higher risk.
With respect to valve on/off issue, I like to adhere to the following policy:
A) always check your valves are all on (or the way you want them - like stage pressurized but off) before donning your tanks and again right before you go under (with your hand and/or by breathing each reg a few times).
B) NEVER let a deck hand / dive master or anyone who is not you touch your valves, especially when you are about to go underwater, and especially after you’ve already done your last-minute valve check for yourself.
C) if you can’t reach your own valves to turn them off or on, you NEED to rearrange your gear such that you can. This enables the implementation of guidelines A and B and enables you to better deal with any valve-related issues that may arise mid-dive (roll-off, leaky valve, leaky 1st stage, free flow, etc).