Ideas and suggestions.

A very nasty exploit has been discovered. The host accidentally clicks the "Restart" button. They have no restarts left, and the opponent didn't request a restart. The opponent can't do anything about it. There's no save file. It's impossible to prevent. In tournaments, this is critically important and can sometimes add a significant percentage to the chances of winning. For example, if the host realizes they've restarted and are already noticeably behind on the first day. The only solution seems to be adding a restart confirmation and requiring confirmation from the other player as well. P.S. "Accidentally" is used as an explanation: "Sorry, I looked in the wrong place."