At a recent Marriott Courtyard bar conversation during a hockey game, a lady asked me if I knew why they spell the team the "Toronto Maple Leafs" instead of the "Toronto Maple Leaves". I did not at the time but it comes down to not understanding some of the finer grammatical rules of the English language. If a noun like this is related to a name, not an object, then the rule is to add an "s" to the name. The name here is "Maple Leaf", the Canadian national symbol.
The same logic applies to "Mickey Mouse", which is pluralized as "Mickey Mouses", not "Mickey Mice".
A more in-depth explanation can be found at this link.