Ross, you and I are in 100% agreement on this issue. Almost 30 years under my belt using not only the green bottles but the much more intense Mapp gas bottles on torches(along with countless other much larger bottles of much more explosive stuff) and can not begin to fathom why boaters in general are so freaked out about propane. Especially 1 lb disposable bottles.More on the order of 250 psi.
If I were to carry them on the boat I would store them in my propane locker along side my twenty pound tanks. I use a propane torch to light my charcoal grill fires and remove the torch from the tank every time! I also use the touches for plumbing work and carry one in the car. In Thirty-four years in business I have never found an unexpectedly empty tank. I have no idea what you guys are doing but my experience does not support a concern for tank safety.
I suspect the biggest problem is the same as many other boating related problems, lack of common sense.
Common sense should dictate that you toss out those partially used 1 lb bottles after the season(or weekend), they're not that expensive. For God sake don't be stupid enough to refill a disposable bottle. What part of disposable are some of us not understanding?
If you are really that freaked out by storing propane on your boat try this idea. Take it home and store it in the garage when you are done sailing at the end of the day. I'd suggest storing it right next to the half empty 3 to 6 gallon gas can for the outboard motor you use to power your boat out of the marina.
For those of you that have experienced problems with the valve not seating when you disconnect the regulator might I humbly suggest if it happens on your boat while anchored out somewhere. Toss it overboard far from your boat and loved ones. The same thing I'd hope you'd do if your alcohol stove had a catastrophic failure and your boat was in eminent danger of catching fire.