"An honest mixer"

Surely an oxymoron.
Can't think of any reason other than illegal that would require coins to be mixed. But am prepared to be educated otherwise.
Don't be one of those.
Just because people want privacy, doesn't mean they are doing something illegal.
If that were the case, we would make rest room walls and stalls all transparent.
Just because something is illegal in some state somewhere doesn't mean it's wrong.