I regularly compete in the US [long trip!] with autonomous 1 lb and 3 lb machines. They have a class for fully autonomous machines which compete only against other autonomous machines. It's great fun. For heavies at present I think that Will, above, is right. Semi autonomous has potential but you still want to have a person driving the machine. And of course there is the safety aspect - you don't want to come anywhere near an autonomous machine unless it autonomous functions have been switched off and you know they are off.