All manufacturers of an emissions defeat device are under the scrutiny of the EPA right now. If they haven't been contacted directly, they will shortly.
Any kind of Off-Road or Racing exemption forms signed by the end user are NOT seen as a valid solution in the EPA's interpretation of the Clean Air Act. Under this act, a race vehicle must be used SOLELY for racing purposes (cannot be registered for highway use). Other than that, you are NOT allowed to alter or defeat an emissions control device on a motor vehicle.
At this time we have not heard anything that would lead us to believe the EPA will attempt to fine an end user that is illegally using a device. But we do know they will be tracking down the product manufacturers to stop production.