Users can see a room is busy in a calendar in Outlook 2013.  However, they would like to see who reserved the room in order to negotiate a different room.  How do you go about seeing who it was that reserved the 'busy' room?

The "owner" (or admin) of the room calendar must grant "Reviewer" permissions to the users.

https://support.office.com/en-US/article/Share-an-Outlook-calendar-with-other-people-CE386FA9-04E3-43A2-8B08-A6B1CE9CA86D#__toc375058250

Set a room mailbox to show limited details of a meeting:

"Set-MailboxFolderPermission -accessRights LimitedDetails -Identity Room:\calendar -User default"

Jani