Apparently Cisco layed off all of their PIM engineers
"It can also block new requests to join a multicast if they would impair video quality."
Um...No. If one user on a segment, be it wired or wireless, is receiving a stream, that stream will traverse the network through a possibly predefined path, given intelligent (or at least informed) network admins. Once that user is 'watching', any number of additional users on the same wired/wireless access device can watch with NO INCREASE in network bandwidth on any of the affected segments between the stream source and the user.
Sounds like marketing bullshit to me.