3.Mixing codes?
It's been repeatedly stated by multiple competitors that mixing codes can't link your transactions and they don't involve storing any logs. How does that work? Is it possible to mark certain coins so they are not later sent to the same depositor, without knowing exactly which coins those are? I don't think so but you could easily prove me wrong if that's not the case.
That question has never really been answered. The first time I've seen it, was
July 2, 2017. They (the biggest mixer at that time) didn't answer the question, but
closed shop 3 weeks later.