When it comes to larger tanks, it is extremely important that they are level. Most blowouts occur due to too much pressure on a particular side of the tank. Also, if your lighting is too hot and is heating up a plastic brace, the brace will begin to warp and breakdown.
But ya, just the thought of that much water on the floor is a bit nerve wracking, especially when you hear a weird sound in the middle of the night, lol