Quote from: Peter R on May 19, 2015, 01:36:39 AM

The reason is that coins are always blacklisted in retrospect. By the time the coins are blacklisted, taint will have already diffused across previously-white coins. If these coins are suddenly un-spendable, then the currency system is pretty useless.

exactly right.

also, think about the edge case where an attacker decides to send blacklisted coins to every known address in the system. are all the UTXO's in those addresses now tainted? given my emphasis on UTXO's being the more valid way to conceptualize this topic, blacklisting addresses doesn't even make sense.