This issue is vastly aided and exacerberated by the fact that immediately after unskilled laborers land, the first procedure is their passports are seized, and it's made clear they have to please their employer and work themselves to death to get it back. It changes the entire dynamic straight away: instead of the employer being obliged to keep you, you are now obliged to get back your passport.

Yes, there are other factors such as bonded labor, indemnities and local laws taking precedence. But this is such an obvious abuse factor, it makes sense to remove it. Of all the ways to do it, whether it's paid lockers and so on – what the parent comment said is still a cheap way.