I would love to have a general conversation around mixers and if they are legal. I've heard both sides. Would be great to have someone involved in the legal side of things like Ciphertrace or a regulator to shed light on this topic
They're not illegal unless they operate where they need a license as a money handling company. Just like casinos and exchanges aren't, if they don't obtain the necessary licenses.
But legal or not, if you knowingly help criminals facilitate their business, then yeah, you're going to get a call from the police some day. Ciphertrace is working with them as a paid agent now.