I actually found some good information on how the whole capless system works which makes me feel better. I don't have the link still but it was right from GM. Most systems have a spring loaded door with a rubber seal on it where the gas nozzle has to go through, so there is some force involved etc. GM has 2 of these doors \ flaps not just one making sure dirt \ water doesn't get in there. There is a gap between the outside and the actual flaps as well to allow dirt \ water to fall through before it gets to those flaps and into the tank as well. The system has been around for quite a while, I wasn't aware of any of this. It's also nice because you don't have to worry about losing that cap or getting the dreaded engine code that shows when the cap isn't on! I still kind of want something to cover it because i'm funny like that but it sounds like they really thought this through and you don't NEED one. I would appreciate something that held the gas door closed instead of just a spring though, I want to keep the inside clean regardless.