Rewe is one of the better stores for this. Even though it didn't seem the staff was explicitly trained on that topic (the feature was just switched on one day),

Rewe is one of the better stores for this. Even though it didn't seem the staff was explicitly trained on that topic (the feature was just switched on one day), the register showed enough information that they knew exactly what to do. Never had any problems, only surprised looks. The other store is Aldi (actually both of them), where from day one every single cashier was trained very well on that and was happy to see a customer actually using it. All the other stores created many opportunities for mistake by staff they badly trained and much confusion still happens today even long after the roll out. Most commonly, many cashiers demand a signature (on the back side of the receipt, where there is an authorisation text for using another payment technology) even though none is needed.