In general, when discussing a question and it is not stated that the context is the US and unless explicitly stated otherwise: is it assumed the governing law is US patent law and that the question is domestic?
Speaking only for myself, I do not feel the there is a default venue on this site. Some of the most prolific contributors are from countries other than the US.
I normally ask the op to clarify if I suspect they want to have a US answer.
If not, I try to answer generally. There's really not so many questions where the law differs substantially between US and Europe and it's not clear from the question which is meant. Other jurisdictions would have to be specifically mentioned, but are rather rare.