Visa and Mastercard have restricted their cardholders from making purchases on AllofMP3.com, the russian music website that's selling single song mp3's for as low as 10 cents a track (and now moving to a free model). Are there other examples of credit card companies taking proactive measures to bar their cardholders from using their cards to make purchases that might ultimately be deemed illegal, though the outcome is not ambiguous and undecided at that point? It's either socially responsible or risk averting, but nonetheless an interesting decision.