We have been coming to Munich as a group every November for the last 20 years. There's a regular trade show here. Most years we come to the Muenchner Gesellenhaus for one of our meals. It's close to the hotel. Good Bavarian food at good prices.
This time (November 2015) we noticed fewer people in what is usually a very crowded restaurant; could just be chance. The menu seemed smaller than usual. Has there been a management change? Anyway, the food was still good, schnitzel, sausages, pork knuckles, the usual stuff. No prizes for sophistication, but at around $40 per head for two courses and a couple of drinks, not bad. Service was good too.
Then time for the bill, and suddenly it's "sorry we no longer accept credit cards". OK, a few restaurants don't, but we checked and there was no sign on the door or windows. So cash it had to be, unless you have a European bank debit card (I do). This is the restaurant's choice, but they should at least make it clear before you eat. And if you come from outside Europe in a large group, someone needs to bring a ton of cash, or you'll be collecting it from each other and trying to keep track of who paid what.
There's loads of great Bavarian restaurants in Munich, so we'll probably pass on this one in future. I did politely tell that to the waiter and asked him to pass the message to his boss. I prefer to give both positive and negative feedback directly as well as on Trip Advisor.