For most events, Robin tries to update the event organizer's calendar when meetings end early, extend or change in other ways. This has benefits over an update to only the room resource's copy of the event. Here is a typical example:
Alice schedules a 60 minute meeting on her calendar and invites the conference room. The meeting ends 30 minutes early. She presses "End Meeting" on the room display as she leaves the room. Robin changes her calendar event to end at that time. This updates the schedule of everyone invited, including the conference room.
Robin changes the organizer's event, not only the room's copy, so everyone invited also gets the update. Alice's calendar always shows her real availability to co-workers. The same applies when Robin clears everyone's schedules because a meeting is canceled for no-shows.
For events booked through Robin (for example, room displays, web and mobile apps), the booking user is the organizer on your behalf, and these permissions are given by default. If Robin cannot edit the organizer's event, it updates the room calendar's copy instead.
See how changes cascade
Google Calendar shows this clearly. Here, only the room's event is edited, and nobody else gets the update:
When you update the organizer's copy, the change shows everywhere:
This permission is important for user-to-room and user-to-user scheduling tools. It lets your users schedule without confusing workflows.
References
See Sharing and Attendees from Google Calendar.