Do journals in general have any kind of policy regarding papers submitted by someone without a research affiliation?
Some journals implement a double-blind reviewing process, meaning that the reviewers are not aware that the authors are from academia or not, and only the scientific content is judged. That being said, it's worth mentioning that it would be hard for someone without a proper "paper-writing" training (such as the one one can acquire in academia), to produce a paper that would be accepted by reviewers. Some general structure is expected, such as related Works, critical discussion, rigorous methodology, and I would say that without that, it would be hard to get the paper published (I have myself rejected papers from graduate students, not because the idea itself was bad, but because the structure and the presentation were not meeting the standards one could expect for a scientific publication). 

EDIT: After reformulation of the question, assuming that the quality of the paper makes it indistinguishable from any other paper, then, no, as far as I know, there is no general policy regarding the official affiliation of the author(s). For instance, in Computer Science, it's not rare to see papers published by people working in a "normal" company (i.e. not a research company), typically on some concrete problems/solutions they have found. Some people even keep publishing after starting their own startup, and therefore the affiliation is something like "MyCompanyWeb2.0".