My apologies, that was a bad typo. I meant that it should always
be moved empty. I realize that it cannot be moved when full, but I wondered if it would be acceptable to move with the sand bed still in the tank. It sounds like it would be a bad idea for reasons other than structural integrity, though.
FWIW, here is the link and the relevant statement:
(The 8 and the ) got turned into an emoticon.....)
Aquariums should NEVER be moved with any amount of water or substrate in them as they will be quite heavy and you can risk injury to yourself or damage to the aquarium from the shifting weight. Always move your aquarium when its empty of water and substrate.