Which resort are you staying at? We use RAC all the time. On one trip, while we were staying at Saratoga Springs, the RAC people gave us incorrect boarding passes and checked our bags to the wrong traveler. My husband has a very common Hispanic name, and there just happened to be another person by the same name traveling on the same airline (SW) on the same day, to a different city. The boarding pass was no problem since I had purchased the early bird check-in, but I was really concerned about the checked bags. We went to the check-in counter for SW, and the guy there gave a little rant about how he didn't like the RAC program, that Disney doesn't know how to do airline check-in, and so on and so forth. I think the agent at SSR realized the mistake right away and had tagged all 4 of our bags to me. Our bags got home fine.
RAC works really well when it works. You are completely checked in and don't need to stand at the airline desk at the airport. You just go directly to the TSA line. Since our experience at SSR, I make sure I see that they tag our bags while we are standing there, and check my boarding passes before I walk away.