Personally I will never put another locking gas cap on any car I ever own (and I live in New York), where some "quality individuals" have been known to play, lets experiment in your gas tank. The reason why is because a couple of years ago I had one on my Corvette....shhhhhhhhh..uhhhhhh....yes I have owned a couple of Vettes
Well it was the correct cap made for the car. So one day I went to get gas, removed the cap, but I couldn't see the filler entry tube for my tank, there was just a solid piece of metal
What wound up happening was the cap was not vented correctly, and basically created a "vacuum like" situation within the tank, and the entire gas tank had sucked in like someone letting the air out of a balloon, it was unbelievable. It turned out to be a manufacturers defect within the cap itself, but it certainly left a bad taste in my mouth about locking gas caps.
just my 2 cents
Laura