Can't say I'm surprised by that in the slightest.

What I would be interested to know is how an exchange or other service that has to yield to this would treat coins that come either from mixers that ignore this or are mixed crowd style a la Coinjoin. Would they be automatically obligated to reject them? Will there be a point where you need a completely unbroken trail to go anywhere near a centralised service?

It's same old fungibility question. Where does it begin and where does it end? I can see it becoming an impossible mess unless everyone's sensible.