If the Knights Templar operated what were essentially proto-banks at the time of the Crusades, how did they deal with fraudulent letters of credit?
Did they have any kind of law enforcement mechanism – like sword-wielding Dirty Harrys – to make sure fraudsters were caught and punished?
If so, what? If not, how did their banking system work without it?
My WAG is that these letters were difficult to forge. They would all be dripping, literally, with apparatus of authority, wax seals of the nobles who issued the letters. There wouldn’t be many of these lying around. And whoever picked up the money would be part of a retinue rather than some shifty-eyed proto-UPS delivery guy.
As for enforcement, they were the fighting knights. They could handle anything themselves. Which was another good reason not to cross them.
At the withdrawal point, simply showing up at the door with a note from the grandmaster for 700 livres of gold would not be sufficient. I imagine that without other means of verification, personal contact with the Templar bankers was extensive to insure that the withdrawer was who he really claimed. Also, the kind of people that the Templars banked with were generally prominent types and would be well known. Certainly, they would have a sufficient entourage to show that they were men of means and this would no doubt be a pretty high hurdle for a con-man to leap. When some noble going on crusade got his note of credit from the Templars, it was no doubt a big deal and they may have given him letters and news to deliver to the Templars at his destination. Not having such things in one’s possession at the withdrawal point would most likely be a suspicious sign.