People knock the guy but he is not blackmailing anyone to go on his show. They proactively apply to. They know exactly what they are letting themselves in for. It has been on air for 6 years.
And watching the early morning repeats (5.00 am!), it seems that some of them go back for seconds. Someone on this thread said that he he takes advantage of those of low intelligence. I think some of the "guests" could be accused of the same thing. I am assuming ITV picks up the tab for all the DNA tests, lie detector tests, the after show psychological support, rehab etc. etc.
A lot of them also seem to make the most of the hotel stay the night before, which I assume ITV also pays for.