Originally posted by Glenn Fisher:

It would be nice to have an official ruling on that permissibility, even if the plan is to tell players “Don't do that!” either way.

I think that Scott's comment on this scenario, which strikes me as a bit (or perhaps more than a bit) of a corner case, is reasonably satisfactory that this is permissible. It's a bit strange to have this kind of situation happen, and I'm not sure the MTR could ever do a good job of covering such a situation at the same time as preventing behavior we don't want.

The players are indeed playing a game of Magic to determine a winner, albeit in a rather unconventional manner. Perhaps there is a small window for shenanigans, but weighed against the players goal here of making the best of the situation, I'm comfortable with allowing this to happen.