[mbell]

You wouldn't even need direction antennas to do this, just some number of reasonably spaced omni's that could feed signal strength information. The problem with this approach is that the wrist band needs to transmit to make this at all useful which adds cost to its design vs being a simple receiver only.

I mentioned this in another comment but it should be easy to correlate a seating assignment to a wrist band MAC giving you reasonably good location information. It wouldn't work "in the pit" obviously but you would be very hard pressed to get any accurate enough location data in an area like that.