This is bollocks
Unless the two punters they've nicked had sniffed and broken WEP, they weren't stealing in any definable or legal way.
Rather, they were receiving an amateur broadcast from an unlicensed transmitter. Any pillock can work this out, which makes one kind of wonder exactly why the Old Bill don't go and do something a bit more bloody useful?
Unless they were just nicking motorists again and needed an excuse.