But technically do you think this adversely effects the electricity company? If not, it's just overspill.
"Velemu says: There was one case in Finland in The 90s, where someone did this to power their summer cottage. When Power company found, where the extra parasitic load came from, they sued the guy to hell and back again. This kind of load is actually actively measured by Power companies, since it is also used to find other failure modes on powerlines, and is easy to detect. Just don’t do it…."
1. If the outputs of the 'collector' go open circuit (because the rectifier/capacitor/whatever dies) the voltage at those terminals is going to rise theoretically towards infinity - insulation breakdown and discharge will occur which is likely to result in a fire.
2. The current generated by the 'collector' is going to be proportional to the transmission line current; if a ground fault occurs on the line the current in the collector winding is going to spike up to some silly level; that will probably result destruction of whatever is connected to the collector outputs and subsequently a fire.
In far field (like typical radio broadcasts), there's no "coupling" between the transmitter and receiver so the former just radiates its power and cannot distinguish whether it's being received.
In near field (RFID etc.), there is a coupling and the transmitter can definitely tell whether a receiver is present and absorbing the power.
Thus, and IANAL either, but IMHO harvesting from the near field definitely seems more like stealing, while the far field doesn't; is it stealing to effectively recover "waste energy" that would otherwise just be dissipated uselessly, and wouldn't cause any measurable increase in consumption from the power company?
The UK Wireless Telegraphy Acts made it illegal to listen to something that you weren't meant to by fiat without need of any proof of harm AFAIK, so there could easily be random laws in various places outlawing this extraction of power that has to be made up by other generation, even if small.
You generally aren't allowed to extract even small amounts of power from the system unmetered with a wire either, without specific permission.
Generating power from far fields does not seem likely to get any meaningful yield. I remember my father showing me how to build a passive radio receiver using a strong sender nearby and it worked. No other power source involved but you could listen to the (weak) output. So in theory possible, but not really useful.