Here's a setting people are welcome to use:

The "cult" mentioned in my story "The Business Trip" got its start way back on 21st-century Earth as a college sorority (I'm tentatively calling them Delta Alpha Epsilon as according to a quick Google search that doesn't already exist). At first it was just a barefoot-centric group, but that was hardly unique and felt a bit too casual to the organization's leadership. They created strict rules forbidding members from ever wearing shoes, but it wasn't enough.
Desperate to not fade into obscurity and to cement their ideals, the leaders trained themselves for a year to use their feet in place of hands, and after a year they threw an intense private party at which they all amputated one another's arms at the shoulders. After this point all new members had to submit to the same procedure.
Unfortunately, all too often members would regret their choices, leave the sorority, and attempt to sue them. At some universities students were getting their amputated arms regrown and suing anyway. This was hurting the group's reputation, greatly decreasing new pledges, and threatening to ruin them, so using all the remaining clout they could muster they struck a deal with every university that hosted a chapter. A complex induction process was put in place.
Every year during rush week, if there is any shortage of new pledges, existing members select a number of on-campus resident students and quietly break into their dorm rooms in the night. They anesthetize the subject and spend the night stripping her and placing her in a torso cast that completely restrains her arms like a straitjacket. They also place walking casts on her feet so as to prevent her from wearing shoes. From that point forward she is cared for by one or two existing members for the rest of the semester as she gets used to using her feet in place of hands.
At the end of the semester is a party for all new pledges. Most notably their casts are removed, but there's also a great deal of sex and drunken revelry. From this point until the beginning of the Spring semester is a trial period during which they get to think over whether they want to pledge themselves to the sorority. All are required to remain barefoot until the beginning of the Spring semester, otherwise they must start the induction process over again the next year, even if they meant to decline membership. The trial period coinciding with Winter holidays helps ensure true devotion from prospective members.
At the start of the Spring semester is the final induction party at which everyone who successfully made it through the trial period has her arms removed at the shoulder and becomes a full member, and again there is much celebratory sex and drunken revelry.

Eventually said sorority develops into the cult-like organization that colonized Risa 12.1 and established its strict barefooting, arm amputation, and NanoBlock laws.

I wanted to write this out as a full-fledged origin story, but I've been much too busy for months now and don't see myself having much time to write it any time soon. Thus I've posted this synopsis and hereby declare the setting free for any authors here to use.
Inspiration for bits of it came from several sources including a story on DeviantArt about another barefoot sorority and a picture by Excilion of two students whose arms had been casted as a prank.