Sure, this is awesome for espionage, playing jokes on your neighbors, etc. but how about running an experimental cellphone network that can provide service for not only VoIP handsets but also old GSM phones? It’d be great fun to build a renegade cell network using throwaway old GSM handsets and cobbled-together VoIP devices / homemade phonebooths.
NB: <a href=”http://news.ycombinator.com/item?id=1565819”>One commenter on hackernews</a> pointed out the different types of phones that would allow this hijacking. Good to know.