JIT Conference Room Scheduling

It has been my experience that finding a meeting room at a company can be next to impossible. All of the rooms are booked all of the time. This has two effects:
1) More meetings are held virtually, which is less effective IMHO.
2) Groups waste lots of time walking around looking for space.

It is my contention that meeting rooms, despite being perpetually reserved, are in fact underutilized:
-Recurring meetings are canceled at the last minute.
-Recurring reservations are made with no intention of actually meeting every week.
-Meetings take far less time than scheduled.
-Users book rooms that are larger than they need.
-etc.

My idea is to optimize the meeting room reservation system for just-in-time fulfillment. Here's how it would work:
1) When you schedule a meeting, you request a meeting room near your location. No room is assigned at this time.
2) 10 minutes before the meeting starts, the system locates a room based on location and the number of confirmed in-person attendees.
3) The systems sends a text message to all attendees, giving the location of the meeting.

Additionally, users could text the system to request an impromptu room for X people near their current location (using the phone's GPS location if possible).

Pre-reservation of rooms would be disallowed except for very large groups, such as all-hands meetings, or meetings requiring special equipment. Pre-reserving would require elevated permissions.

To prevent rooms from remaining reserved after a meeting has ended early, the system offers two mechanisms:
a) Users can text the system when their meeting ends to free up the resource.
b) Rooms are reserved for 15 minutes by default. A text message informs the user when their reservation is about to expire. The user can respond to extend it.