I used to be a regular guest of this controversial hotel, mainly because it's one of the very few in Amsterdam that offers a wired high speed Internet access in every room. However, it proved to be almost impossible to survive more than one day in its “solitary cells.” So I began to book double rooms instead, paying the higher room rate. But these too never were really comfortable. It was only until recently that I realized what was going on. Last September I arrived twice for stays of two and five days in double rooms. Both times the (friendly) receptionist replied to my question about the type of room I was given: “It's a superior single”, and added that it was a large room. The first time I accepted this because the stay was short and I was curious about the quality of the accommodation. Well, the room had twin beds with a few square centimeters more space around them than the average single room. Upon the second arrival I was of course not willing to accept the inferior room type again. A rude guy who is not often seen at the front desk intervened and offered me a free upgrade to a double room. How generous. An upgrade to what I had actually booked and guaranteed by credit card! The room I got then was better than any of the other ones I had been given in the past.
It seems that the hotel silently changes the reservations of individual travelers. Most guests probably don't verify the room type upon arrival. So they remain unaware of the overcharging. This presumably happened to me quite a few times before I started to ask questions.
Due to the ongoing tourism boom in Amsterdam, the demand for hotel rooms is constantly high. As a consequence, many hotels have become greedy and don't care about business integrity. My confidence into the “Red Lion” is gone and I will look for another place in the future.