The claim was that she could perform the dowsing, not that she could perform the dowsing in case the entities chose to. If the claim were the latter, she'd won the MDC. So, from my point of view she was wrong about her ability as per the claim in question.
You're being pedantic, but that's your right. I'll join you. She performed her end of the contract flawlessly. She was not required to dowse the cards correctly - she was required to make an attempt should she deem the conditions suitable. The results of her attempts were to then be evaluated. She did not breach the contract in any way, shape or form.
So, why should she apologize for fulfilling a contract? Had she passed, would you expect the JREF to apologize?