anytime ETC moves all one needs to do is bother an Exchange and say that they are stolen funds on the move.

The ETC coins that the Smartest Player rightfully won in the DAO game (by following the rules as plainly stated and re-stated many times by Stephen Tual and other DAO creators in the terms of service) are only a small fraction of all ETC.

Once those ETC are traded, they are no longer "his" ETC. To justify the freezing of some funds traced to those coins, the entity requesting the freeze would have to show that the current owner obtained them illegally, or that he was aware that they were somehow obtained illegally by the previous owner. That's because ETC coins are fungible: in particular, one cannot claim ownership of specific instances of the coins, but only of a certain amount of them.

If somehow some court can be convinced that what the Smartest Player did was a theft, then he will be ordered to return the amount that the court decides he has stolen. The victims then will have to accept the refund in any form or currency that is possible; they cannt demand to receive the "same" coins.

(All the more so that, AFAIK, Ethereum does not work with UTXOs, like Bitcoin, but with account balances, like a bank; so that all coins sent to the same address are autmatically mixed together even before being used in any transaction.)

The rest of the ETC is not "tainted" by that incident, and the gamblers have as much right to gamble them as the ETH and BTC gamblers have the right to gamble those coins. (If somehow the ETC were to be classified as "criminal" coins, then every one who owned ETH before the fork woul be a criminal, and every one who sold his ETC has profited from a crime, and should return the money to the victims.)