AppleTVs, and other iDevices communicate by mDNS which is a form of traffic that is essentially broadcast only. This works flawlessly in a home environment but falls apart quickly in an enterprise environment such as Morningside College where we must segregate the network into multiple pieces. As such, AppleTV's are a bit hairy on campus. They only work for clients on the same VLAN, and when they do work they are globally visible making the list of airplay devices about ten miles long.
Today, Nick and I registered all institutional Apple TV's in Clearpass guest (http://clearpass.morningside.edu/guest). These devices are shared globally within their AP groups, which correspond to buildings. The practical upshot of this scheme is now, from Lewis Hall, I now see this in my AirPlay menu instead of all devices on campus (pictured, right).
At the moment, only members of the department may register devices and Nick Buth is the current registration expert.
In the future, it is anticipated that we may allow students to register personal devices that may only be visible to themselves and up to about ten persons of their choosing. Caveat: Per-user authentication only works on the Morningside wireless SSID.