If someone is giving me fiat money, I know that I can spend that money as easliy as I got it. The same thing should be with Bitcoin, so how are we going to handle with this issue?
Not necessarily... If someone gave you a pile of fiat that was splattered with some bright colored dye or paint, such as what happens when a bank robber flees the scene of the crime and opens their bag of ill-gotten bills only to find an exploding dye canister going off in their face and all over the bills, would you really expect a bank or merchant to accept those "tainted" bills? This is the fiat equivalent to "tainted" Bitcoin.
I haven't personally decided if I support the idea of "tainting" bitcoin yet, but this would be an example of the real-world equivalent.
Isn't this the MAD (mutually assured destruction) escrow thing again? A robber breaks into a bank, only to discover that there are no piles of cash lying around on the floor (unlike a certain web service that got cracked recently...), and that the money is locked away inside an indestructible vault.
In the end, the robber manages to take the entire vault with him. Upon hearing about this, the bank manager gets really pissed off and has the key melted down, thus making the stolen cash inaccessible forever. And everybody lives happily ever after.
