The structural problem is that the tenant is buying exposure to an asset somebody else still controls. During the option period the seller holds the deed. The seller's mortgage, if there is one, stays in the seller's name and is the seller's to pay or not pay. The property taxes are assessed to the seller. Any lien recorded against the seller during the period attaches to the property the tenant is paying toward. The tenant has a contract right and no ownership, so if the seller stops paying the mortgage, the foreclosure runs against the seller's title and can wipe out an unrecorded contract right along with it. The FTC lists this among its named warnings, alongside the possibility that "the 'seller' doesn't really own the property," that "the owner hasn't paid property taxes," and that "the house is in terrible shape, or has issues like lead or asbestos."
The rent credit is funded by the tenant, and the arithmetic is worth doing before the emotional case is made. In a typical deal the rent is set above the market rent for a comparable property, and the excess is what gets credited. That is not a subsidy from the seller; it is the tenant prepaying their own down payment at the cost of not being able to invest or hold it. The test is not whether the credit is generous but whether the total of the option fee and the credits is money the tenant could keep if the purchase does not close. Ordinarily it is not.
Most of the failure modes are timing failures rather than fraud. The purchase price is usually fixed years in advance, so the tenant carries the risk of the market falling and captures the benefit if it rises. Mortgage qualification has to happen by the option deadline, and a tenant who was not mortgage-ready at the start frequently is not mortgage-ready three years later, particularly if the higher rent prevented them from saving anything else. The FTC's warnings include being "locked into paying more than the home is now worth" and finding "you can't qualify for a mortgage to finish paying off the house." Its other warnings concern the contract's own terms: "promised fixes aren't made after a contract is signed," and "if you miss a payment, the deal is off."
Repairs are the clause people skip. A rent-to-own contract commonly shifts maintenance and repairs to the tenant, which is unusual in a residential lease and is defended on the ground that the tenant is the future owner. The consequence is that the tenant funds improvements to a property they may never own, and a dispute about whether a repair was required can be the event that terminates the deal and forfeits the credits. Anything a seller has promised verbally about repairs is worth nothing unless it appears in the document.
The protections that do exist come from ordinary law, not from a special regime. Recording the contract or a memorandum of it, where state law permits, puts later buyers and lenders on notice of the tenant's interest. Requiring the credits to be held in escrow rather than kept by the seller changes what happens if the seller fails. A title search at the start shows whether the seller owns the property and what is already recorded against it, and a current tax status check shows whether the taxes are being paid. An independent home inspection before signing does the same job it does in a purchase. None of that is standard in these deals, and each of it has to be negotiated in.