Thats not so, blacklisting increases the probability that you receive back blacklisted coins— even if you didn't have blacklisted ones going in. This increases the "cost" to you of using this approach, so only outlaws will think it worth the cost, and so you'll only receive outlawed coins while using such a system. It's self-fulfilling once it takes off.  I don't think that things that have cost and take effort and which only a tiny fraction of (more likely than usual to be troublesome) users can really move the needle against efforts like this, or at least we shouldn't count on them to.