11/2007 I had no problem either in Argentina to withdraw +320 pesos from ATM's with Maestro. Problems started 04/2008. I do not need a PIN with my German Maestro in many places within Germany. Even if it has a chip and provides for PIN. Seems like some German merchants are still in the process to implement PIN function yet. Maybe in Portugal they thought it was a credit card

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I've even been able to pay on Maestro in Norway and Denmark on signature...