Not that I know of (although some venues require it for unloading at a bag and tag regional). It would however be a really bad idea to not have a cart. Your drivers are going to be running all over creation for 3 days, and the last thing you want them to have to do is carry the robot the whole time. Pushing robot along the ground is also generally not recommended, as it back-drives the motors which can make the speed controls "unhappy." If you want to be safe, you need a cart. Some teams go all out and build glowing carts with power plugs etc. (like my team
), while others go really simple and cheap. If you search CD I'm sure you'll find lot's of examples/pictures.
Good Luck!
-Luke