In support of your comment, why can't apple have a few DIRECT EMPLOYEES at each major supplier factory full time to monitor the working conditions and terms adherence on a day to day basis ?
As a manager have you ever tried to change the behavior of even a single employee?
If there is a culture problem with the management, an observer won’t solve that.
In any case, how would that solve anything?
Can you think of a single example where acquiring a problematic company solved its problems?