Neat find by Derick Okihara, writing for AFP548:
In addition to bonjour negotiation for AirPlay, iOS 7.1 devices will also look for AirPlay sources over bluetooth when doing it’s scan! This means you do NOT need bonjour to AirPlay.
AirPlay is one of the best parts of the modern Apple ecosystem — a complex system neatly wrapped in a simple “it just works” interface.
This new feature by Apple helps with networks that turn off Bonjour over UDP, which has been a common complaint previously.