I had a 29 g that I was moving from my old studio upstairs to my new studio downstairs.. I drained it down as much as I could (the only water left was in the gravel, which I left) I moved it on the workbench that it had been on, and wheeled it down the hall to the freight elevator.
the problem came when I tried to get off the elevator.. the wheel snagged on the threshold and the whole aquarium toppled over..
the moral of the story is that unless you want to clean up a whole freight elevator (or living room) of water, gravel, flourite, sand and broken glass, empty the whole thing. I thought I was in the clear.. I found out the hard way that wasn't the case.