"Obscurity" can be a function of several factors.
"Who was standing to the left of Character A when he bought his coffee in Episode B of the series 'C'?" is obscure for anyone except dedicated fans of the series "C", and should be disallowed, IMO.
For me, pretty much any question involving sports is difficult, because it's not an area of interest for me. Personal strengths and weaknesses shouldn't, of course, be a criterion for labeling a question "obscure."
What's common knowledge in one country is a mystery in another, as in the case of the "Railway Cuttings East Cheam" question. In that case, my opinion is that it should have been allowed, as FunTrivia is an international site and should contain questions appropriate for all members. If I, as an American, miss the question, it's my opportunity to walk in the shoes of non-Americans dealing with questions regarding "I Love Lucy."
We forfeit three-fourths of ourselves in order to be like other people.