i've had the same set of denvers on 2 cars now (2007 rabbit and 2010 golf), done about 60k miles on them with rotations every 5k, a few alignments and 2 sets of tires (so a lot of on/off /balancing with these wheels...). i had never lost a center cap until my last rotation/balance, when i noticed i was missing one a day later. they were all there after i got the car back from the dealer, and after snapping a replacement cap in i'm convinced they don't just pop off on their own. they are in there REALLY good. i think the dealer broke mine in some way that allowed it to go back on the wheel, but not as securely as it would normally fit. somewhere along the way the broken cap was dislodged. my theory, anyway...