Well there isnt said that this situation happened in The West game.. It could happen in real wild west. A man left his town and went on a journey. then someone challenged him for a duel. EZ solution.
The player must have opened the advent calendar before it should and the game itself puts a bounty on that player even if he or she out of town. So anyone must have been duelled that player because of that bounty.
The yearly Advent Calendar put bounties on the heads of townless players if they opened a Calendar door early, thus making them fair game for duelists.
During the advent calendar, if you open the doors too early, the system will put a bounty on you.
So you're gonna have a bounty on you, can be dueled even without a town.
Opening wrong door on Advent calendar (when the date that does not match the door number) automatically creates a bounty on the player who made this mistake. It makes possible for anyone to duel this player even if he/she is without a town.
The duel was initiated before he left the town!
With automation, you can schedule 8 long tasks (like traveling the map bare-foot), and then finally the duel. This would take a long time to complete and would register as a valid duel