I get the breeding thing (hadn't thought of that) but can't you show a dog that is not yours? Or run them in agility? For instance if I had Sca jumping (more than he does already) could a friend take him to agility and enter him if I was racing?
As y'all can tell I am new to this stuff and am a bit clueless. Sca is scheduled for a life of harrassing his sheep and being spoiled with no mini-Sca's (though maybe some SheltieCross)
There is no rule that I'm aware that requires the owner be present or be the one showing/competing with the dog, I think it was a personal choise that Deb and Mike made. It's a way to let them share in the dog's accomplishments together.
Personally, if I was going to train and spend months teaching a dog to do agility and then compete with him/her, I'd like to be able to have that pride of ownership that would go with it, a way of acknowleging all the hard work they each do with their shared pet/furbuddy.
) could a friend take him to agility and enter him if I was racing? 

) I am sure the grooming lady will remark on what a fine looking character he is despite him needing a bath. So even if it is not stated maybe he does have two houses (though one has a cranky Shihtzu in it)