Yes, you can debate how much imported (or for that matter, domestically produced) stuff is actually tested, but the fact remains that existing laws and regulations do cover this, even if enforcement is maybe lacking.

I'm an ham radio operator, and shortwave spectrum pollution is sadly a big problem despite very strict regulations.

The unfortunate reality is that the market is flooded with noisy devices, often cheaply produces overseas, that vastly exceed legal limits (chargers and other rectifiers, plasma televisions, powerline adapters, and much more).

Enforcement is difficult due to how widespread these devices are.

In many places, the noise floor is to high that long-range shortwave radio communications all but impossible.

Or cheaply produced in the US... Most tech I've bought from Shenzhen recently has been of better quality than domestically produced equivalents

I think police cars should measure it.

It can take hours to pinpoint the location of a specific transmitter with skilled equipment operators.