Hi Mats,
Yes, on BIM Server if a user has at least Project Administrator Management permissions, he is able to see and join any of the projects. It is by design setting for Simplified Permission System what BIM Server uses.
However, on BIMcloud it is possible to use the so called Detailed Permission System, which allows you to configure more precisely what your users can access. For further details I would suggest to contact your local distributor.
Kind regards,
Noémi
Noémi Balogh
Community Expert, Admin