In a make-to-stock vertical contracting setting with private contracts, when retailers do not observe each other's stocks before choosing their prices, an opportunism problem always exist in contract equilibria but public market-wide Resale Price Maintenance (RPM) can restore monopoly power. However other widely used tools which do not fall under antitrust scrutiny and require only private bilateral contracts, such as buyback contracts, also allow the producer to fully exercise his monopoly power. We conclude that a more lenient policy toward RPM is unlikely to affect the producer's ability to control opportunism.