This thread caught my interest. I am just throwing out ideas here:
- One way is to use "guest access" entry/exit status. If you did sign in and sign out in a system that could be used to deny access when you left the building.
- There could be a simple time based access setup. You may have had access only for the duration of the meeting.
- Some vendors also use RFID choke points to determine the physical location of the user. Either inside or outside a given room.
- One could also use RSSI based location information to make that determination. Although I haven't seen a whole lot of accuracy using only RSSI based calculations.
- Is it possible that you were seeing the signal from a different AP when outside the building? If so then, it could simply be a matter of tying access to point of entry into the wireless LAN system.
I am curious to know what you find out.