Yeah, but those of us with MkIV Jettas and Golfs and stock steelies have pretty secure wheel covers. Oh, and Passats too.
I lost one only when I got a flat at speed (And my friend found it on the way to work later the next day).
They ARE plastic, but they have this tensioned steel wire ring that keeps the numerous plastic fingers on the back hugging the wheel. If you lose one of these hubcaps, you didn't kick it into place evenly all around, or your wheel/tire it's on is <bleeped> anyway (see above).
The cool kids with their alloy wheels wouldn't've had these, if their car rolled off the lot with OEM alloys, or if they were fitted aftermarket alloy wheels.
And they're NOT cheap to get either:
VW Volkswagen 99-06 Jetta 15" hubcap 1J0-601-147-N-GJW
Mine for my 2000: $70 *each*
Another style, another site - looks more like a Passat style cover: $40 *each*
