"We are not aware of any abuse by these companies." - seems to be carefully worded. They do not make claims that there are no abuses, nor do they elaborate what checks/audits they have in place to detect abuse.
How can any honest people make such claim? It is the same as proving the non-existence of abuses.
They could probably catch 99% of abuses by just specifying it in the contract with the 3rd party, but they have't done that.