When Kerrie Evans’s child was born with cystic fibrosis, she sued her nurse practitioner and doctor for failure to adequately inform her about prenatal testing for CF, making concerns about cost the centerpiece of her case.

Her complaint stated that genetic counseling was covered by her insurance (to rebut the defense claim that she declined counseling due to cost). During voir dire her counsel said that Kerrie couldn’t afford the child’s medical expenses and therefore had to sue the providers. Counsel’s opening statement included the claim that Kerrie couldn’t afford the extraordinary care the child needed. On direct, Kerrie testified about her insurance coverage, describing out-of-pockets, co-pays, and scope of coverage.

But when defense moved, outside the jury’s presence, for permission to cross-examine Kerrie about insurance coverage, her counsel invoked Montana’s collateral source statute, insisting that the defense couldn’t ask Kerrie about her insurance coverage.

The court granted defendants’ motion to a limited extent, allowing questions on whether Kerrie had health insurance and on policy provisions, but not on amounts paid by insurance or coverage limits. The court also limited the inquiry to Kerrie’s claims for emotional distress, since she based that claim on anxiety over the child’s unaffordable medical care. The defense asked five questions. The jury rendered a verdict for the defendants.

On June 27 the Montana Supreme Court affirmed, citing an exception to the collateral source statute: the “rule of curative admissibility, or the ‘opening the door’ doctrine,” under which the introduction of inadmissible evidence by one party allows an opponent, in the court’s discretion, to introduce evidence on the same issue to rebut a false impression that might otherwise result from admission of the earlier evidence. In some jurisdictions it’s known as the “sauce for the goose” rule.

The case is Evans v. Scanson, No. DA 16-0363, 2017 MT 157 (Mont. June 27, 2017).