I am not surprise as I have heard stories of this sort in Malaysia as well. I was with a friend and when the police stopped him, he asked " what's the going rate now". I was taken a back but kept quite. He spoke with them in Malay and I guess they are bargaining. Eventually a price was agreed and he paid. They do not have a 3 days pass like yours in Thailand. If a little money can help to make your trip less stressful and enjoyable, then pay them to prevent harassments. Probably their salary is so low that they are trying to make some easy money. Good luck to all. Take care when you are on the road.
Thanks for sharing @jackpot