Yes so buy a used one and have it rekeyed if you can find one. Or an aftermarket like others have said.
Depending on where you are, it might be illegal to ride with out a lockable fuel cap... Or at least one without a latch. It's like I said a serous safety issue.
Illegal meaning not road safe or "dot" approved for on road use.
Just food for thought
Pinwall cycle is worth a look, but given how long these bikes have been out it's not likely.
Crazy thought (most of mine are)- is this something that could be re-created with a 3D printer, assuming you could borrow one? If so, I guess how the plastic would react to fuel would be another concern.
This is now my 5th reason to BUT by or another modification must for the 2.5's. I wanted to buy one so bad but the 5 or 67 serious issues that either the dealer wont or are impossible to fix are a deal breaker, all of them make the bike unrideable. a non removable cap is a must for me, for this threads reason.
IMO there is no reason why they should have done away with the old style caps.
$15 Amazon pop-up gas cap for the win! This isn't over, but this will get me by for as long as I want to use it.
Kucehiup Motorcycle Clockwise... Amazon.com
Rode for 20 minutes with no issues and no codes. Some details: 1/3 tank of gas down to 1/4 at end and gas light came on as normal, 100 degrees out, bike warmed to full operating temp during ride.