Edit: I see the headline (probably written by someone other than the author) says they "invented banking". There are of course many claims to that dubious honour!
This incentivizes banks to "know your customer" (long before modern regulatory regimes), as well as for banks to only deal with other reputable banks. In legal jurisdictions that do a lot of international commercial transactions, rules such as these are typically held paramount unless specifically and clearly overridden by local law. Relatedly, jurisdictions that don't abide the so-called Lex mercatoria tend not to become centers of international commerce.
If the drawer weren't strongly protected, the utility of checks would severely diminished.
Worth bearing in mind the type of people using this service were landed gentry. A Turkish bandit wouldn't do well turning up at a Templar fortress trying to redeem some French Lordlings's gold but you still have to expect unscrupulous Europeans would be stealing from each other.
I'd expect the KYC was pretty strong at the issuers that handled gold/property. Your family would be known, not just the individual. I think they were redeeming food/lodgings/services while on route so defrauding a remote fortresses might not be at all rewarding. To score big I think you'd need to present as landed gentry at places like London which sounds hard... your target would need to have no friends/relations... but it's the premise of 1000s of historical fiction novels so eh?!
Wax seals and such were the authentication tools at the time. It might hobble attempted fakes but I would assume thieves would steal the cygnet rings and such too. I've seen claims the Templars used cyphers but that type of history gets blurred with the romantic stories. Encoding a password onto the cheque seems painfully obvious to us today.
I imagine there was a chain of custody of the person themselves. Templars were protecting the pilgrims not just their gold so they accompanied them from location to location so the chance of someone unknown turning up at a gate with cheques to cash is less likely. I also imagine they were in groups with others of similar stature with similar arrangements so the difference between an authentic wealthy traveller and a chancer might be quite vast. I imagine there was a network of letters between Templar sites tracking the notable Lords so faking your way into someone else's identity would be quite tricky.
From what I gather, it foremost may simply have been a risk based business where the vast profit covered the losses.
Spot on.
It's actually mentioned in the article:
"The Templars were not the first organisation in the world to provide such a service. Several centuries earlier, Tang dynasty China used "feiquan" - flying money - a two-part document allowing merchants to deposit profits in a regional office, and reclaim their cash back in the capital."
Essentially, the Roman Catholic Church turned a blind eye to the Templars usury, largely because of the value provided by the Templars in enabling an endless stream of warriors for Christendom. They did set some arbitrary limits on the amounts that were permissible, but didn't have much in the way of methods of auditing or enforcement.