[RFI] Computer cases and RFI

[Alan NV8A]

In my local independent computer store today I saw a variety of cases 
for the build-it-yourself types (among which I include myself), but was 
surprised to see some totally transparent ones. I asked one of the store 
employees whether these had any shielding (e.g., in the form of a 
transparent metallic coating on the inside), and he said he was sure 
they did not and that he would not want to use one himself.

So here is the question: computers are supposed to comply with FCC 
emission regulations, but how can a computer built into such a case 
pass? Granted that home-brew computers don't get tested, but can a store 
legally sell someone a custom-built computer (this store does: you 
choose your case and what components you want in it) that could never in 
a million years pass the FCC tests?

I wonder how many such RF-pollution generators are in use.

Alan NV8A