Travellers 'just like you and me' - anthropologist
Social anthropologist Michael Stewart has worked with travellers throughout Europe and has two years experience working on a council travellers' site.
He says he does not speak for travellers but has studied them and tried to see things from their point of view.
He said they avoid conflict with other travellers and were "just like you and me".
Mr Stewart told BBC Wales' Week In Week Out most travellers treated their workers well, but in Darrell Simester's case it was clearly exploitative and abusive.
He said relationships could be complex. He has come across another case in London when a man lived with a family for 30 years - who was in one sense a servant and in another part of the family.
Week In Week Out is on BBC One Wales at 22:35 GMT on Tuesday 4 November.