I understand your point perfectly. I suspect that you don't understand the context of a collegiate competition. It's a very different culture than regular amateur competition. Impromptu entries are not only acceptable, they are encouraged. People enter events with pick-up partners all the time. They even often have partner matching at the competition for people who came without a partner. It's all in the spirit of the collegiate competitive culture which is largely about generating excitement in new dancers and everyone dancing as much as they can. On more than one occasion I have been coaxed onto the floor for events I wasn't formally registered for or planning to dance at college competitions by either friends, the crowd, or even the organizers. It's all in good fun!