Porbably I might misinterpret the initial question. Let me explain how I understand it...
There might be an addon, which sterams from another add-on which is on the banned list. For me, that means, that both add-ons (the potential one and the banned one) needs to be installed. Otherwise the 'potential' add-on can´t choose the other add-ons as kind of a source. If that´s the case then your Kodi installation will become unsupported at this forum.
If the potential add-on you are talking about using the same sources as those which are on the banned list, it will end up at the banned list itselft as well and you Kodi installation will also become unsupprted.
In any way, if an add-on provides copyrighted content (either if it does that itself or using another service/add-on/whatever) it will end up on the banned list.
As you are talking about "streams", I guess it´s all about video content?!
If we are probably talking about UPnP and probably talking about to choose "Play with" and selecting another Kodi instance as the UPnP client and that said Kodi installation doesn´t have any banned add-ons on it, then:
- the Kodi installation which is the UPnP client is not unsupported in here as it doesn´t contain banned addons
- the Kodi installation which is the UPnP server and contains banned add-ons is unsupported in here
- any upcoming problems with that way of using UPnP is also unsupported in here as well as the source of that stream comes from a banned add-on
Sorry, if I might have misinterpreted your question