If they deny fewer claims then medical expenses will rise for their self funded employer customers, and then those customers will switch their health plans to a

If they deny fewer claims then medical expenses will rise for their self funded employer customers, and then those customers will switch their health plans to a competitor like Cigna or Aetna. Most coverage rules are driven by large employers. UHC would be happy to offer a health plan which paid every single claim if that's what employers wanted: it would actually mean higher profits for UHC.