Q: How can reserve a piece of equipment (such as a projector) for a meeting without sending a meeting update message to all the attendees?
Exchange can't tell the difference between a meeting room resource and an equipment resource. Exchange treats all resources as though they are meeting rooms, so the system informs all meeting attendees of all resource additions or changes on the assumption that they need to know where the meeting is located. If you do not want the attendees to receive update messages when you book equipment for your meeting, you can create a new meeting in your calendar to book the equipment.
Note: If your meeting is canceled, you will need to be sure to cancel both meetings so the equipment will not be reserved for a meeting that no longer exists.