After all I wasn't that much off, my theory was that anyone in a crowded environment (bus, train, etc.) could get a "payment" by simply being "near" the card (be it in a wallet , in your pocket or in a bag).

The objection was that there were much more sophisticated controls by Visa on the "other side" (reputability of the account where the money would go, etc. ) and that the sheer number of micro-payments needed to make the theft profitable (and thus the number of complains) would have easily triggered off the various automated alarms.

But if someone can obtain a Visa/bank account and credit it with a small number of (delinquent) transactions each of relatively high amount, get the money and close the account in a short time it can probably become viable.