Well, it finally happened. Last night I was driving on a back road, and hit a gnarly patch of pavement. Two of my wheel covers went flying (left front and right rear). I was able to recover them both, but one of them is broken beyond repair.
The one on the right went into a ditch, and I had to fish it out. The one on the left went off into the woods. Walking along a dark road at night, searching for car parts, wasn't exactly my idea of fun.
I was originally going to bolt the pizza pans to the wheels, but changed my mind because attaching them to the trim rings was "less permanent". But the wheel covers have proven to be effective. So the next step will be to bolt them to the wheels, like I originally planned.