It seems like the loophole they used was getting you into combat before you entered the Boston claim.
If you were on foot you would not be able to enter the Boston claim because you were in combat.
In a boat however the in-combat check before entering the Boston claim doesn't seem to function. Just like you get no notification when entering a Village claim while in a boat, and you are able to enter a pclaim over water whilst in a boat.
In short, don't get put in combat. You won't escape unless you have better phlegm and can run very fast. In a boat you will never escape.