Happen to me too. Nobody blew up about it...we were doing RVs in the car group and the other couple ended up calling on the same house I was going to. I ceded it to them.
People take magazines mostly to end the encounter...most JWs realize this, but are then obligated to make them a return visit. Some people just take the magazines to be nice and support the apparently friendly JWs who sometimes come to their door.