One thing is that the UPnP API, though undocumented, was available to everyone who could figure it out. That has benefited them tremendously because Sonos is very widely supported now and a safe bet for most automation systems from Crestron down to open source. A lot of folks worked hard, without any help from Sonos, to help them move boxes.

But, if they start getting uppity and will only allow large companies to have access to this new API, they are going to have a lot of PO'd customers who are no longer going to be able to integrate their Sonos boxes.