Methods and apparatus for communicating with a receiving unit

At least one computer-readable storage medium having instructions encoded thereon which, when executed in a system comprising at least one computer, cause the at least one computer to perform a method comprising acts of:

• (A) during an event at which each of a plurality of users is provided a corresponding wearable receiving unit, causing at least one of the wearable receiving units to manifest a first state change via transmission from at least one first location of at least one electromagnetic signal to the at least one wearable receiving unit;
• and
• (B) causing the at least one wearable receiving unit to manifest a second state change at a time other than during the event, via transmission to the at least one wearable receiving unit, from at least one second location which is different than the at least one first location, of at least one signal by a mobile device in response to a determination that one or more predetermined criteria relating to an environmental condition detectable by the mobile device have been satisfied.