Continuity mistake: When Elmer walks up to the row Bugs and Daffy are sitting in, you can see Bugs is holding a carrot in his left hand. When Bugs says "Who, me?" after Elmer asks him if he was Bugs Bunny, the carrot has disappeared.
Continuity mistake: When Daffy is horrified to see Bugs' name on Elmer's red book and not his, the words "Bugs Bunny" are on the front, although when Daffy took the book from under Elmer's arm, the front was completely empty.