First, it's the EPA that's cracking down, the FBI wouldn't be involved in environmental issues. Second, the EPA has done away with the "for offroad use only" safeguard. Third, the EPA has practically put an aftermarket company (Casper's Electronics, a popular company among the Buick folk) out of business for their sale of emissions-altering, or "defeat," devices, so of course BBK, Vortech, etc. are complying.
#07-490: 07-10-07 Federal Settlement Targets Illegal Emission Control “Defeat Devices” Sold for Autos