I recently did a System Center Service Manager 2012 SP1 install for a customer that has a blanket policy of denying interactive logons to all service accounts in their domain. The first issue that we ran into was that the Service Manager Data Warehouse could not be registered. After allowing interactive logon, it registered fine. We also hit a snag where the AD connector wouldn't start synchronizing until interactive logon was allowed. The workflow account will also fail at various tasks when denied interactive logon.
The moral of the story is that you should not deny the "Logon Interactively" right to your SCSM 2012 service accounts!