Usage of Admin project

Hello,

I use an Administrative project to store all activities like holidays, training, etc. which are outside of regular project scope.
Great future in Real Work Allocation (RWA) is that all users can by default log work on this project, without needing to manually affect & assign them.

However typical use case that I don't know how to handle is concerning holidays: sometimes (too often !) team members will leave on holidays and they forgot to log that in RWA before leaving. So the PL must correct this for end-of-month validation, by opening the Team Member's sheet and logging work.

Question is: unless I'm mistaken, if the PL is not manually affected to the Admin project, he cannot log work on holidays for the team member. Is there a way to avoid the manual affectation ?
(note: I use "Elements of own projects" for the "Access on real work allocation for resources" parameter for Project Leader)

Cheers