Recently, it seems that they have largely abdicated that responsibility and do nothing to stop those kinds of exploitative landlord practices.
ALL landlords in Provo now require a 12-month contract (you can't just rent for the school year like you used to be able to do), and this kind of 85% fee nonsense seems to be more and more common.
If you are going to continue to require all unmarried BYU students to live in BYU-approved housing, then you need to use that approval as leverage to force landlords to treat students fairly, otherwise the landlords are going to use that requirement as leverage to squeeze students for every penny they can get.