https://transition.fcc.gov/eb/jammerenforcement/jamfaq.pdf
- For example, jammers can: prevent your Wi-Fi enabled device from connecting to the Internet
- A jammer can block all radio communications on any device that operates on radio frequencies within its range (i.e., within a certain radius of the jammer) by emitting radio frequency waves that prevent the targeted device from establishing or maintaining a connection.
And more is in there. Judging by these definitions the FCC believe they have a pretty wide reach:
- Any device that jams or disrupts cell phone calls, text messages, or other wireless communications by emitting an interfering radio frequency signal is illegal
As you stated, the courts would have the final say.
I guess with a 'Monetary Forfeiture' being the punishment I have to retract my suggestion. You are better off breaking it with a rock, spear, or a shot-put!