I have pictures of one that "failed" around somehere (not my house, thankfully), but it was just a 7/8 empty 100 gallon tank. The damage was mainly structural: unbeknownst to the owner, a joist started cracking under the tank and the owner noticed that the waterline was different in the tank. The 2-3 mm difference wasn't enough to cause a concern, and he only noticed it when he was doing water changes and it got near the top rim. A few months later the corner seam opposite from the corner of the room that the tank was housed in gave way from the torquing and the owner came home to the last of the 75 gallons of water that ended up on the floor dripping out through the seam.