Recently one of the planes on our flight school line was found with a ripped right elevator skin inboard next to the rudder about 1/3 of the way up from the trailing edge. The rip was about 4" long. At first look it seemed as if someone pulled up on the elevator from between the skin when the gust lock was in. I spoke with a mechanic who said he had seen this before and it was a weak point in the aircraft in 1977. He said that they can rip by themselves, and Cessna installed a baffle plate in later models to alleviate this poblem. Has anyone heard of this or know of any documentation supporting it?