I have said for a couple of years now that the real money will be made by somebody that develops a “drone killer”.
“Yessssireeee folks rat chir we got the best drone killer on the market, homes in and knocks down any drone under 500 feet, garrrrrannnnnteed!!!!! Only $29.95 for the base unit with re-loads $5.95 plus shipping and handling.”
The R/C aircraft community used to have a problem with that some years ago when there were a limited number of frequencies. Remember the guy at the beach who did not like seeing the gliders and would jam them. As I recall the FCC did nothing so some guerilla action was required. Damn near burned the house down.
Kinetic kills are impractical in anything other than rural areas. It would have to be a comms link jam and that cannot be limited to 400 feet AGL. It would not down the drone but would cause it to abort its mission and RTB