Current support for reservations in UNICORE uses user's account to create or cancel reservations. This is a sensible default, however in some setups it is desirable to have a special user to perform those operations. The problem is in fact on schedulers side where reservations creation is often simplistic and often only a dedicated user can manage reservations. This is a common case for Maui (one can either enable reservations for everybody or for a specific user) and as far as I understand docs also for SLURM (the only option is the dedicated user). Both schedulers are used in PL-Grid.
So having an option to configure a dedicated reservation user for creating and canceling reservations, will allow us to use the rich UNICORE authZ for controlling reservations creation access.