Exchange 2010 calendar meetings - allows meeting to be sent then sends decline message

Question

We updated from Exchange 2003 to 2010 last year and are still trying to figure out how to make the resource rooms work properly.  In 2003, if you tried to schedule a meeting and the room was not available, it would not let you send the request. 
2010 does and then sends back a decline message.  Can this be changed to be like 2003?

Answer 1

Is there not a way to have Outlook reject the meeting before sending it (like exchange 2003 did)?  I know you can see this in scheduling assistant but not all users use that unfortunately....they just type in the names and send.  Before
in Exchange 2003, it would check availability before sending and NOT send the meeting at all if the room was not available.  That is what I would like to get back to. 
Nope. Not possible in Exchange 2010 or 2013 using the built-in Exchange Calendar Asst features.  Direct-booking is not recommended and Outlook 2010 and above do not allow it by default.
That is by design, allowing the server to manage and handle the meeting request logic. 
The reason being is that there is now built-in delegate moderation, in-policy and out of policy requirements etc... The resource mailbox has no way of knowing if the meeting request meets or fails the requirements without receiving it first. 
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