well if we want to get technical here, the basic premise did not give us enough information, while we do know that a tent was set up, we dont know for a fact that the people were sleeping in the tent. That is an assumption.
Secondly, if the people were not sleeping in the tent and were looking at the sky, they would not notice that the tent is missing unless they had some fantastic peripheral vision.
lasltly even if we are to assume that the people were actually sleeping in the tent and the tent was missing, we can not categorically state that it was stolen, it could have been blown over by wind, it could be repossessed.
so while the joke was recycled, we can not say that the engineers observation were 100% common sense. It is just an assumption. 
