[rpierce]

Slips on by in the press release:

It is a violation of federal law to market, sell, import, or use a signal jammer in the United States and its territories, except in very limited circumstances involving federal law enforcement.

It seems that nothing is more common than seeing the words "violation of federal law" these days.

[Eric in the Ozarks]

Police radar jammers were once commonly sold in the US.
I don't see them advertised anymore.