[AdmiralGinge]

I wonder how much it'd cost for them to license a tiny part of the low-frequency radio spectrum? The one for BBC Radio 4 covers most of the country with a single transmitter for example, using this old-school technology you could report your battery's serial number as stolen (with the appropriate authentication) and the company would broadcast a signal to short it out. This would be much harder to defeat than an internet-based solution I think.

[rowanG077]

It's trivial to defeat with a faraday cage.

[AdmiralGinge]

Not if you want it to actually fit in the socket of a car or bike.