Actually, LL DO go to pains to point out to you that your IP address can be obtained via the media stream:
Or, if you don't want to read the whole page, here's the relevant bit:
Voice, web, audio, and video streams do not pass through Linden Lab's servers; they are accessed directly by the Second Life viewer. One way to keep your content secure is to use one of these distribution methods.
Streaming content attached to a land parcel can use https to provide a secure stream, and is not routed through Linden Lab's servers. The Second Life viewer pulls the streaming content directly from its source.
Important: Conversely, the owner of a parcel of land may use their streaming media source to determine your IP address. If you are not on your own land, you may choose to disable reception of streaming media in the Second Life viewer's preferences.