Not sure why I'm still arguing with you even though I should be working but anyway... you are making a few incorrect assumptions: 1) it is somehow possible to prove beyond reasonable doubt that the origin of the coin is fraudulent, even after gazillions of complex transactions; 2) there is always going to be an exchange involved in these transactions (or some other "cooperating" entity); and 3) the entity attempting to exchange the coins is somehow related to the fraud and should be punished. As I mentioned above: Who decides that "an address involved in theft, fraud, etc."? What happens to a legitimate merchant who sells a product or a service to one of the addresses "involved"?
What happens to a buyer who pays in bitcoin and never receives his product? A vendor that has one or two bad transactions might get away with this, but on a large scale, they will not. How is this any different from other assumptions of fair play with this or any currency? If large scale theft goes completely unchecked, then the currency loses value. Taken to the limit, it has no value. The "1 to 2 hops" I originally mentioned certainly aren't "gazillions" of transactions. I've read your responses to "comeonalready" in other threads, don't waste you're time trying to troll me, just stick to reality.
Actually, I just logged in to catch up on this thread, and I'm leaning toward suchmoon's point of view on the topic, but probably only as it tends to reflect my own personally held opinions. (And also because I usually tend to side with whomever is invoking the fewest analogies in an argument, as they often oversimplify the situation at hand.)
Unlike everything I usually argue in favor for (yeah, sure), there are probably no easy answers to the questions being posed and that each of you are arguing for what you believe in, rather that what is enforceable, as there is currently no oversight authority of cryptocoin by anyone who can enforce any rules, even minimal standards of ethical behavior.
There are a few things I would like to point out... If someone is found to be in possession of illegitimately obtained cryptocoins, and it can be proven that they were directly obtained in an illegitimate fashion, whether by stealing hashpower to generate them or by stealing the coins right out of someone else's wallet, they should be prosecuted and their illegally obtained gains confiscated (and returned if possible) -- but there are already laws on the books in many countries for theft of possessions or utilities, computer crimes, trespass to chattel, etc. with which to pursue them. Others having knowingly accepted stolen cryptocoins should be penalized in some form too, but as knowledge and intention are difficult to prove, confiscating cryptocoins from others down the chain at any level is not likely a possibility in the near future. The only reason that charge backs are possible with credit cards is because merchants sign legally enforceable contracts with transaction processors requiring them to agree to such provisions in order to accept any payments at all. There is no such requirement with cryptocoin yet, nor may there ever be.
This more regulation / less regulation argument has been well underway within well established markets for centuries, and it is still going on to date. Unless rules or measures are baked into some new cryptocoin algorithm from the very beginning, it will continue to be a point of contention for the foreseeable future. Cryptocoin is a big ugly mess, but so is the real world, and it probably needs our attention first.
Update: Now that I've read the Galileo remark, I take it all back!