I hope you realize that in addition to being bad for those who exploit grad students, it is also bad for the marginal grad student who is no longer going to be able to go to grad school. For a lot of us foreigners, grad school in the US is essentially our only ticket to a life in the first world. So I implore you to consider the impact of a policy that results in fewer grad students on the marginal ones - typically foreigners or minorities or females in male heavy fields.