One article in the April 2022 issue of the Journal of Shintō Studies was about the Naoi Matsuri at Owari Ōkunitama Jinja. This matsuri was revised by the local daimyo in the 18th century, and the revised version is still held today — it is famous as a “naked festival”, which means loincloths only.
The main interest of the article is in the contribution that a particular person, an important scholar, made to the revision. It was known that he did contribute, but the documents he submitted have been lost. The article reconstructs his likely proposals from surviving documents that reference him or seem to be based on other things he wrote.
That’s all very interesting, but the matsuri itself is never described in full. Putting together the references, it seems to have gone like this.
Once a year, dozens or hundreds of men associated with the jinja would arm themselves, and then go out in roving bands to find someone to kidnap and force to participate in the matsuri. They could be local or a visitor, but they had to be an adult man, and not someone with enough political influence or connections to get the jinja in trouble. That person would then be taken back to the jinja by force, and made to carry the sins of the area in some sort of earth mound. (The details are very vague here.) Stories current at the time suggested that he was sacrificed and eaten, but that does not appear to have been the case. People did, however, fight back to stop the jinja taking anyone from their village, and people were injured during those fights.
The revision was that the scapegoat should be a volunteer, and be paid for his trouble.
In general, I prefer that legal authorities not interfere with religious practice, but in this case I can see their point.