In South Africa we had 4 dogs, An Alsation, Alsation cross Lab, pitbull and a german shepard cross rottie, we kept them segregated as they fought sometimes, sometimes we would come home and 3 of them ( not the pitbull ) would be sat in the drive waiting for us. We wondered what the hell was going on, as time passed we found out. It was the Gs cross Rottie, he had worked out howto free the bolt on both the gate keeping him and the other 2 and the knock-over clasp on the drive gates.
Clever dog that