Biggest concern is for people with cable tv or internet services. Working for a cable company, on more then one occassion technicians randomly showed up at a growers home to determine source of rf interference. You see if its bad enough it will not only knock out your services, but also backfeed into the local system causing other people problems. They refer to it as 'killing the noise floor'...One case customer was using 4 Solis Tek digital ballasts, which should be shielded well. Only flaw seemed to be they were located 5 foot from where his drop from the poll entered the home. But it's easy enough to test...if your having tv issues or internet speed issues while your ballasts are on, and not when they are off, you have a pretty good hint. Satellite, Wifi, DSL all seem to be immune based on their operating frequencies. Something about cable networks that makes them prime to pickup the noise.
Oh and in case your wondering... the solution was typically to install rf filters on the cable in home, effectively reducing the 'antennae' effect of the home wiring. As far as I know, our company had no interest in reporting the grows, simply wanted a working cable network for the area. People who denied entry to home for privacy reasons had services terminated to prevent the back feeding.
