I’ve tried to rent sailboats three times. I have no paper qualifications at all, but I have a lot of time on the water in a variety of vessels, in a variety of roles. I've had more than a dozen boats of my own over the years, including home built.
The first place where I tried to rent a boat, just said no. This was for a 30-something foot boat in the Caribbean, back in the 1980's.
The second place rented me a boat after a short conversation, but gave me a boat with a damaged back stay. When the wind got over 6 or 8 knots, I ended my day sail early & brought it back. They didn’t think that a damaged back stay was really a cause for concern, but they voluntarily credited me for half the day’s rental fee anyway.
The third place said no at first, because they only rent to people who have gone through their own training course, but no course was available for more than a month. We wanted a boat that day or the next day. The place had plenty of 22-25’ boats available on the dock. When I pushed a little more, they eventually found someone to check me out. That person approved me before we even got off the docks, after it became apparent to him that I know more about sailing a boat than he did.
I then got instructions on how they wanted things done. We were given a restricted area in which to sail & I was told to radio in from a mile out & call them for a tow to the dock. They were horrified when I suggested that I could just sail in & do a drop-sail landing. I guess that they have never seen that done successfully. It was their boat, so I agreed to their standards.
A couple of hours later, we decided to drop sails & go for a swim. 10 minutes later, a semi-panicked guy on a jet ski came roaring over & asked us what our emergency was. I said that we didn’t have an emergency. He insisted that having our sails down was a distress signal & call for help. That was a new one on me. Perhaps that was part of their special training course. Perhaps the guy on the jet ski was a product of that course, with little other experience. He scolded us for having the sails down & insisted that we put them back up immediately or accept a tow back to the docks. We put the sails back up & sailed back in.
I haven’t tried to rent a sail boat since then.
I know of a place down in the keys that automatically includes the use of a 22’ sail boat with the rental of a bungalow from them.
The bottom line is this. Rental standards vary from place to place. Some sort of standardization has the potential to be a good thing, but I have concerns over what form that standardization might take.