Disable Resource auto accept email confirmations

We were previously using Outlook 2010 on Windows 7 with Exchange 2010. Our meeting rooms are all set up as ‘Rooms’ in Exchange. When a secretary books a room for the lawyer they worked for, they got an on screen confirmation pop up confirming the resource had been booked. To get this auto accept working when we moved to Outlook 2010, I had to load the ‘EnableDirectBooking’ key into the registry for each user. That wasn’t a problem to me and the system worked well.

We are now upgrading to Outlook 2013 on Windows 10.  For those users, the rooms are not auto accepting the meeting requests (I assume this is more to do with Outlook 2013 than Win10?). Appointments are going into the calendar for the room as tentative and need to be accepted by our receptionist at which time the lawyer (not the secretary who made the booking) gets an email confirmation the meeting has been accepted. Annoying!

I tried creating the EnableDirectBooking key in the registry for Outlook 2013, it did not work. After much googling I understand that Direct Booking is an outdated feature which is why it didn't work. The only way I have found so far to have the calendar appointment automatically accept (rather than going in as tentative) is to tick a box in Exchange for the resource ‘Enable the Resource Booking Attendant.’ However, when I tick this box, the meeting organiser gets an email confirming the resource has been booked. This may not seem like a big deal, but the emails go to the meeting organiser who in my situation is NOT the person who created the meeting. The secretary created it. So the lawyer gets an email that they’d rather not have to deal with. I have found where you can modify the content of the email but not a way to turn the emails off completely.

Is anyone aware of a way to turn the email confirmations off but still have the resource automatically accept the meeting request?