An unauthenticated cleartext audio stream delivered over an unisolated multicast domain? Sounds like you could’ve loaded up VLC and some The Exorcist soundbytes, and had yourself a good old time :-)
An unlocked house next to a street? Sounds like you could have loaded up a beanie and some bag and had yourself a good old time d:^D
To be fair his claim is more like filling their home with packing peanuts. Obnoxious, a crime, but also not on the same scale as theft.
Multicast rtp data perhaps? Maybe they’re streaming elevator music from their VoIP server?