An M365 user with no policy defined uses the global policy. We utilize global policies. For example, our global calling policy allows users to make calls, but not simultaneously ring externally.
If a user requests simultaneous ring, we have a PME job to assign the calling policy to the user that allows simultaneous ring external, but we can't use PME to remove simultaneous ring because the editing template does not provide for setting to the global policy, which is really nulling the policy on the user.