I tell you what they should do..

Develop the system as a Java application compatiable with many of todays mobile phones, using Bluetooth to search for members in range who have the program running also. At a place like Santa Pod you could get quite a range on the Bluetooth

It would basically be a glorified copy of when you search for bluetooth devices in range and it brings up the names of peoples phones.

They could produce that for a much lower cost as there would be no hardware requirement