There's a statement in the UHC release that hasn't received very much attention. It refers to pre-existing coverage for children: "UnitedHealthcare recognizes the value of coverage for children up to age 19 with pre-existing conditions. One company acting alone cannot take that step, so UnitedHealthcare is committed to working with all other participants in the healthcare system to sustain that coverage."
Coverage for children with pre-existing conditions is already in effect but isn't popular with insurers. In 2014 the ACA will ban pre-existing clauses for everyone.
So far, other insurers have been mum on the topic of pre-existing conditions. But health industry stakeholders know it's this type of expensive coverage that will be difficult to continue if the ACA ceases to exist.
And so we wait for the Supreme Court decision.