Notability as defined by WP:GNG means, "If a topic has received significant coverage in reliable sources that are independent of the subject, it is presumed to satisfy the inclusion criteria for a stand-alone article or stand-alone list."
Most of the articles on which I take part can have a simple defense under WP:NRVE "Editors evaluating notability should consider not only any sources currently named in an article, but also the possibility of notability-indicating sources that are not currently named in the article. Notability requires only the existence of suitable independent, reliable sources, not their immediate citation. Wikipedia articles are not a final draft, and an article's subject can be notable if such sources exist, even if they have not been named yet. However, once an article's notability has been challenged, merely asserting that unspecified sources exist is seldom persuasive, especially if time passes and actual proof does not surface. If it is likely that significant coverage in independent sources can be found for a topic, deletion due to lack of notability is inappropriate."
My stance is that as time progresses, information is lost to the void of the internet or whatever method of publication. Articles from pre-internet versus internet era, one degrades slowly the other can vanish instantly. Viewing one material is easy when it exists, the other is often impossible via internet, yet persists. I'll err on the side of caution for ANY claim of sources from the pre-internet era or when such material is unlikely to be available online. Even if this means the article will go without sources for a while. Forums, and other unreliable sources may agree with the article, but they themselves are not reliable enough for inclusion. As is all popularly held knowledge that needs no explanation, such as various children's games which are not the subject of research, yet exist all the same.