Who cares whether a method was overridden or called or whatever -- if it's in the runtime it can be invoked.
API's aren't hidden to make developers lives harder, but rather because they may not be stable and may or may not exist in future releases. And if they do exist, they may not do the same thing anymore.
So, users care. Not about the method itself, but about why their app that they may have paid money for has stopped working after they upgraded their iPhone.