In Lync 2010/2013, our only options for PIN policies are Site-based or the Global policy. The PIN policies should have the same applicable levels as all of the other policies available in Lync (Global -> Site -> Pool -> User). When setting up conference phones (with an associated Exchange resource account), we could disable "Enforce device locking" for these accounts and allow calendar access without affecting the rest of the user population.
Idea No. 267