They really don't seem to care about "moving". My Summer house was located in NY's market area a few years ago. I moved back home as soon as my locals went live. They gave me no trouble with either move.
I don't think there is any benefit to them in trying to detect this practice. DirecTV doesn't lose any money from it. In fact it often means selling local channels to people that otherwise wouldn't be eligible. The only harm being done is to the network affiliates in your market because they loose your eyeballs.