Yes, I think that was 2002 Skate America. Michelle didn't want to do the Grand Prix at all, but she was coerced into it when Sarah Hughes withdrew with an injury and they were afraid the event would bomb without an American headliner.
This was never explicitly admitted by USFS or the ISU, but I think part of the deal that Michelle brokered was that she would not have to compete in any other GP events or the final.
She got 15 points for her win, which put her in the finals (I forgot the details, but I think Elena Liashenko got a 3rd and a 6th in her two scoring events, which put her behind Michelle. Someone -- Onda? also withdrew with an injury, I believe).
Anyway, I'm pretty sure Michelle did qualify for the finals, but she declined to skate.
Michelle got 12 points for the win at Skate America (old scoring system).
Sasha qualified for the GPF with 24 points, Onda with 21, Volchkova with 19, Slutskaya with 16 (she was just beginning to feel the effects of her illness, which at the time she thought was bronchitis), and Suguri with 14. Michelle with 12 was the 6th qualifier. She declined, so Liashenko was next, also with 12 points. Then Onda withdrew due to injury, and Shizuka Arakawa, with 11 points, took the last spot in the final.
At that time, it was possible to qualify with such a low point count because the Single seeds were allowed to do 3 events if they chose. All the Ladies seeds except Slutskaya did 3 events, with the result that two silver medals and one gold (a total 30 points) didn't figure into the standings. In addition, one silver and two bronze medals went to skaters who won just the one medal---AP McDonough withdrew from her 2nd event after winning silver, Alisa Drei had just one event, and Poykio was off the podium in her other event.