When a Cambodian man I was with was arrested for overstay by police at a drugs stop we went to the police station in the back of a police van. The cops asked for 5,000 bt to forget it and he bargained them down to 3,000. I presume he used the 'Mother Hubbard' negotiating gambit (the cupboard is bare). Since it was my 3,000 I consider this a result. He did offer to pay me back but I said no to that as he didn't have much. As others have said, 'bail' can be a flexible concept.