Matters needing attention for three people staying at Renaissance Kowloon Hotel in Hong Kong, especially what is the so-called extra bed fee for the third person?

I've tried this situation, but I booked a double room with two beds. I went with my friends. He brought his girlfriend, and I shared a bed. At first, the man said there would be an extra charge. My friend said I wouldn't spend the night here. After that, the man won't ask. I told you, it's best to register alone, and then let your wife and daughter come to your room to find you. If it is a tour group, there is no way out, because they have a commission.