While I've paid for most things in cash, I used my Mastercard at a Кофе Хауз (Coffee House). I checked my online transactions to verify charges and found that I was charged once for our lunch, but again for a slightly larger amount later that day (perhaps someone else's lunch)! The second charge is not mine, an unauthorized charge for sure, but the vender clearly had my card number as we'd been at the shop earlier in the day. I've promptly reported the mistaken charge to the credit card company, but am interested to see how this plays out. As an aside, most banks are now charging 1-3% on transactions for card usage abroad (New Fees For Card Usage Abroad).