We ran into this last night when someone had the poltergeist.
We have always played like the only bridge in the game was the sentinel bridge into the middle region.
One of us had been playing the PC talisman game and insisted that he was able to get rid of this card by going over the very tiny bridges near the castle and village that we had never noticed.
Do these bridges count?
Our group has played over 100 games easy and its amazing that we are still picking up on stuff like this.
Matt