There is a very good chance, that the boat goes not over if you sheet in and hang on line over the winward hull. I have tested it with a H15, me on the main sheet and my crew on the tiller extension - behind the boat and going 10kts or so. I know also from an A-cat which went some miles without crew until it capsized...
Personally I don't like to be tethered to the boat, there is always the risk to get tangeled once capsized.
My rule is, have always a sheet in the hand. And I mean always. Have communication device(s) on you, not on the boat. Tell people that you are sailing. Exercise capsizing until you have confidence in your abilities.

Cheers,

Klaus