Banks are allowed to intervene in payments in certain cases. Sparkasse Mittelfranken-Süd sent a reminder letter because of an AfD donation.
Payments to recipients who are on sanctions lists are automatically filtered out and stopped by the banks. If there are any anomalies, payments can be withheld in order to ask the payment originator again whether this is correct. A bank employee in Hamm recently saved an 81-year-old from paying a considerable sum to fraudsters. It is not always real bank employees who contact customers.