Prevent resource double-booking

This is the way they were instructed to do this.

To set up a meeting:
Be in your Calendar
Select Actions (from top menu)
Plan a Meeting
Add Others
Add from address book
Select Conference Room and place in resources
Select people invited to your meeting and place their name in appropriate place "Required" or "Optional"
Add details, time, subject etc.
Send

This works fine. The problem is not all users are doing this (of course) and we are looking for a way to prevent them from doing it any other way.

That's basically the same thing as completing a meeting request. I would certainly suggest looking at the auto accept agent as we use it and only have read access to the calendars therefore if we select File > Open > Other Users Folder and open the meeting room calendar we can't manually add a meeting and therefore cannot double book as the auto accept agent won't allow this.

But when a user open up a shared calender in outlook and double click on resource calender, he can still book the resource. Is there any way to prevent user to double click on resource  calender?