Of course the client, the agent and the officer involved are outside the strict parameters of the law and could be successfully prosecuted in most countries.
However, this is Thailand, that's how a lot business is conducted. Nobody will be prosecuted/punished unless there is a breakdown in the financial trail.
The dangers for the client, as I see it, is that they can be locked into the system for the duration and it is difficult to go back. It's also possible that one day a crusading politician may change the system.