Did they change it recently? The way i've had attorneys describe it to me before is it is a HUGE issue with the federal government guns + growing regardless if legal or otherwise is a big no no. One attorney told me you can have a legal grow and if you have a firearm at that legal grow and the cops find out, they will arrest you and treat you like a coke dealer. Attorney Robert Correy Jr. is who told me the last part and i've heard from other attorneys he really likes to push the limits.
Am I way off here? I also saw a news article a while back where they were trying to change that, I can't remember how though.