Electricity theft from radar transmissions
Most radars transmit high power pulses but have low duty cycles so the average power is not very high.  They also generally transmit over a narrow beam that is rotated either mechanically or electronically to cover a full circle. Also the power in the beam falls dramatically with range.  Based on those three features, the average amount of power that intercepts a single roof of a house would not be very much. In any event, one would then have to efficiently receive this power and convert it to low frequency AC in order to use it for powering one's household.  I can't give more quantitative answers without knowing the radar parameters and the distance between the radar and the house, but I seriously doubt the story.  Additionally, air defense radars by definition are designed to survey the sky and not the ground.  Thus the radar beam would not be directed low enough to intercept a house other than by sidelobes which are much lower in amplitude than the main beam.