I would think that as a single hander, having the main sheet in if I fell off would eventually cause the boat to head up or flip over, both of which would be better than have it sail happily off on its own.

The caribeaner through the mainsheet/traveler sounds easy enough as long as it won't turn into a tangled mess during transitions. If you're racing, it's probably not needed as others will be on the course. If you're cruising, you probably don't need to worry about a mess as you will be planning your transitions well in advance and executing them rather slowly (and less frequently) in comparison.

I used to have a windsurfing uphaul "scrunchy" that was similar to the custom bungee described above. I guess the question is where would you attach it on your person? Perhaps a coastal cruising safety harness would be appropriate (under the PFD?)

If you're out there single handing, a PFD on your person is a must, especially since your F16 has a boom (or "ow-ie" as the toddler calls it) and you COULD face the possibility of having your "bell rung" if conditions went sideways while you were out (unforseen T-storm, running by the lee to make a drawbridge or tight channel, etc). It also reduces the chance of drowning due to alleged hypothermia (which someone posted some video research that showed people usually die of cold water shock/drowning long before they are considered hypothermic).

In any case, this is a good topic to discuss Pete... Perhaps one day I too shall regain the freedom and joy of coastal cruising around this beautiful coastline... I guess part of this hinges on getting hold of Stefan...