I've been having some problems with the DLC Revolution. I didn't buy it, but today I opened the class creator and I found out I had the Peacekeeper. At first I thought it was an error, but when I started a game I still had it, and it worked. I checked out some other things like maps, and I also had the other Revolution maps. Is this strange or is it supposed to happen?
Is there a different account in your console that may have purchased and downloaded the Revolution DLC? DLC's are shareable to other accounts as long as they are downloaded and installed in the console.
ShadowRonald is right. The DLC is shareable as long as the account who purchased the content is on your console.