Ye gawds. It's just a freakin' piece of cotton. It's not a deity. It's not a spirit. It doesn't contain your soul. It's worth about $5.95 retail or $.03 wholesale.
So what's going on here?
This stuff is foreign and unusual. "Exotic wisdom from the Mystic Orient" or is it "Mystic wisdom from the Exotic Orient". It makes people feel special, important and outside of normal experience. So they invent little superstitions to go with it, explanations and rituals to attach personal significance to the whole thing. This is reinforced by the group and the leaders of the group. It becomes a source not just of individual but collective identity. Each generation adds a little of its own. Pretty soon the whole thing becomes absolutely ridiculous.
A couple other things are at work. First, it represents increased status and skill. Having a new colored ribbon around the beer gut represents initiation into mysteries and increased levels of power. Such things always have ritual and superstition attached to them. Superstition in this case is goes to the etymological roots of the word - that which or one who stands over, one who has witnessed. This increases until one reaches the exalted status of Black Belt. This is supposed to be the culmination of the initiation, resulting in deadly fighting skill, a change in consciousness, acceptance by the Elders and Masters as having arrived and the ability to transmit the magical essence of the thing to others.
Yes, yes, yes. There's always talk about "humility" and how the Black Belt means "You are finally ready to learn". These are also typical of the initiation/ritual process. Almost required really. It means nothing for the most part.
What are the consequences of violating the superstitions? Nobody ever says, which is typical for this sort of thing. There's talk about how it violates "etiquette" or "tradition" or "honor". Does it? Not really. Most of this was added later by successive generations outside of the original culture. Even within the original context these things are often leftovers or served purposes for the people of that time and place but no longer do. By default, when they are emptied of their original meaning these practices become self-perpetuating for their own sake or to the default goal of control over the students. Get them to do one strange arbitrary thing. Then get them to do another. Pretty soon they will do anything.
Sometimes these are important. The military teaches unthinking obedience to create new group and individual identities that will turn regular people into efficient soldiers who will do insane things for a greater goal. The ritual process and initiation are powerful parts of the deep structures of the human psyche. Get them involved and you can bring about useful transformations. Eventually the state you are trying to induce becomes automatic and the need for the ritual goes away except as a reminder.
But a lot of time it's just inchoate nonsense that borders on neurosis. Sorry, kids. That's just the way it is :shrug: