A few people have stated that tapping into the EMF field is illegal. Can anyone point to any actual laws about that?
In the UK, there's the
Electricity Act 1989 and
Wireless Telegraphy Act 2006.
From schedule 6, paragraph 4 of the former:
Where any person takes a supply of electricity which is in the course of being conveyed by an electricity distributor, the distributor shall be entitled to recover from that person the value of the electricity so taken.
and from section 55 of the latter:
the use of the apparatus is likely to cause undue interference with wireless telegraphy
Obviously there's a lot more and the specific parts that could apply in any particular case might be hard to find, but the basic gist is that it's illegal to get any electricity from a power line other than through a normal paid connection, and it's illegal to use any device which is likely to interfere with any wireless communications. The video explicitly shows this device doing both.
It's also worth noting, although I haven't looked up the exact details, that different frequency ranges have different regulations. Some bands are allowed for amateur radio use and you can get away with quite a lot in that area, while the bands reserved for mobile phone networks, TV, and so on, are regulated much more strongly with use of particular frequencies usually restricted to a single company. So a wireless doorbell, for example, is allowed as long as it uses particular frequencies to send its signal, but would be illegal if it used, or even just leaked too much signal into, various other frequencies. And again, note that the developer of this charger says he spent a lot of time deliberately tuning it to interfere with mobile phone signals (although obviously he doesn't use those exact words).
That said, as it stands I suspect it might get away on the interference end of things (but still not the electricity theft end) on the grounds that it's such low power that it doesn't actually produce significant interference, and wouldn't even in large numbers. But the problem there is that, as already noted, that makes it pretty much useless because it would hardly gather any power. Any attempt to make it gather a significant amount of power would of course also make it cause significant interference. So it basically has the choice of being useful or being legal.
If I tune a radio to receive random static am I committing a crime?
No. There are a ton of exemptions, special cases and so on. Earlier versions of these laws existed largely to ensure that you would be able to use your radio at all, so obviously they're written in such a way that normal radio use isn't illegal. They're not, however, written in a way that allows you to remotely drain someone's mobile phone in order to charge your own batteries.
Note that uses such as ben m suggests would likely be OK. If you have a device inside your own building, it's only going to be leeching power from your own power lines, and you'll pay for that just as you would if it was plugged directly into the wall.