Flying Hubcaps

As you know, I travel 580. This past week I noticed hubcaps. I noticed them on the side of the road, only on the left side of the road. Now maybe that is because I drive in the left lane and can't see the right side, so there might be some there as well. But I did start to wonder, how do they come off? Do they fly off like frisbee's? Fhew!! across your hood! Do they wiggle loose and just spin off and roll until they hit the jersey barrier? I counted 15 on the road and wondered are the cars limping around with three hubcaps? And whatever happened to that guy that used to collect hubcaps? Does he no longer do that? He used to hang them on a fence and you could drive there and look for a matching one for the one you lost driving down 580.