Typically shows charge you a small entrance fee. In this particular show there will be 2 conformation shows, lots of speakers, and the part that always breaks my pocketbook a vendor area! Vendor areas typically have lots of cool hedgehog goodies. Things for hedgehogs and things for us! I have a necklace, a couple of t-shirts, and artwork from prior shows. Plus you get to meet a lot of hedgehog people, ask questions if you are new to hedgehogs, and shoot I find that I always learn something new at shows. Either some item that will make my hedgehog's life better or just a trick to handling.
You don't have to bring a hedgehog to a show. I only take hedgehogs to the show if I intend on showing them in an event. For my last show I didn't bring one at all, and if I end up going to Milwaukee Rose will probably stay in the hotel room. My opinion is it is less stress for them. Plus, I usually end up helping folks who have more than one hedgehog to show in a particular category during the confirmation event. Plus I don't have to worry about someone walking off with her while she's in her travel carrier while I'm otherwise distracted (talking to people, etc).
Bryan may be able to comment about registration at check-in since he will be sitting at the check-in table. I don't think I've ever been to one that didn't allow at the show registrations.