Including side-notes about every well-known controversial opinion can clutter up an article and detract from its usefulness. "The Earth is generally accepted to be a spheroid with average radius 6360 km. The [[flat-earthers]] think it is a flat plane, but debate whether it circular, square, or has edges at all. Some flat-earthers think that both sides of a flat earth are inhabited."
It might be appropriate to start a custom of having a section titled "Other Perspectives" or some such at the end of an article, before the references and see-alsos. The body of the article can then present accepted collective understanding of a subject, which most readers will expect to find in a respectable resource, while allowing space to note controversial or popular fringe view. References to that section could be made from the rest of the text.
[To this end, and for other reasons, it would be nice to auto-generate footnotes...]
For instance, one might write: [with autogenerated footnotes]
"Famous impossible constructions include trisecting the angle[[Footnote:#Other perspectives]] and squaring the circle."
==Other perspectives== There are a number of amateur mathematicians, known to others in the field as 'angle trisectors', who continue to work on constructions for trisecting an angle, disbelieving a long-standing (and three-page-long) proof that this is impossible. They are infamous for the persistence of their correspondence with any mathematician willing to review their constructions.