Ecosystem services programs are rapidly increasing and are seen as a pathway for biodiversity conservation based on the attractive idea that quantified values of the ecosystem services of intact land may exceed any gains from conversion to intensive logging or other non-conservation uses. However, I show that, even when all local biodiversity is protected whenever ecosystem services values create greater benefits from conservation compared to conversion, this may lead to poor outcomes for regional biodiversity conservation. I examine this dangerous idea by re-visiting early planning case studies in the Bateman's Bay region of NSW. Integration of ecosystem services into systematic conservation planning typically can ensure good regional biodiversity outcomes. However, as we increase the estimated value of ecosystem services in localities, the region reaches a tipping point where the capacity for good regional biodiversity outcomes collapses. This collapse results because the priority ecosystem services sites tend to represent similar biodiversity, contrasting with the biodiversity complementarity required for efficient conservation planning. Recent proposals for spatial planning that continue to focus only on local win-win outcomes highlight the disregard for planning lessons forged 20 years ago in NSW, and promote a dangerous planning framework where we may never know how much biodiversity we have lost.