I remember reading somewhere that lint might give false positives if you refer to resources in your Java code instead of the xml.

From the README:

If you have references to elements in an old layout that you're not using anymore, you will get a compile error that the ID (R.id.<something>) can not be found. The reason is that the resource file that contained R.id.<something> has been removed as it was not used any more. Time to clean up your code.

If there is a reference to the resource somewhere doesn't that mean that the resource is in use?