Prevent shutdown with systemctl

[Floris <jkfloris@dds.nl>]

Dear list,

Often there are multiple users working on my multiseat [1] system, some of  
them are kids and they are not paying attention if someone else is logged  
in. They can shutdown the computer even if someone else is logged in and  
have an active session.

Is it possible that only root can shutdown/ reboot the computer if  
multiple users are logged in and when there is only one user that user is  
able to shutdown the computer?

Thanks,

Floris

[1] https://en.wikipedia.org/wiki/Multiseat_configuration