It tells on the bottom of the receipt who is supposed to get which one.
They recently changed that - the top copy used to say that it was supposed to go to the host, or HO, or something, but now it says that it goes to the customer. The next one is for the consultant, and the last one is for the host. This is important, because the last one has the CC info blocked out on it, so you aren't passing that around.
Oh - and I stamp my info on the top copy. I love that they've changed it so that the guest gets the top copy...makes it easier. Actually, I've always given the guest the top copy, because that was the easiest one to stamp. But now, I don't have to explain to them that it's okay that they are getting the one that's supposed to go to HO.