Cell phone wardriving/hacking?

So this morning at around 2:30am I was driving back home for my lunch break, and was pulling off Augusta's ring road when I ended up behind a blue sedan with Washington(state) plates. It was moving fairly slow considering there was zero traffic and it was 2:30 in the morning. As I inevitably got right behind it, I noticed that there were six identical cell phones tied to the driver's side head rest, one on either side and 4 along the back, all facing outwards. The rack was connected to a wire that ran out of the car to an ipod-sized antenna on the roof. One after the other each cell phone would dial a random number and then hold the call for about 40 seconds before dropping it and going black for a few seconds. Call, hangup, black, call, hangup, black...repeat. It was rather eerie to watch, and the passenger sitting in the back behind the passenger-side seat seemed to look up and back down every once in a while like he was either controlling them or recording what was going on with them. I was behind them for about 6 minutes before I reached my apartment complex and turned off the road. Has anyone ever seen or heard of anything like this? It just seemed extremely weird and I still haven't come up with any sort of explanation for it that doesn't sound whack.