On a syndicated LMAD during the "Super Deal" era, a contestant wins a car, and trades it in for a Big Deal door; she wins the Big Deal, which includes the car she traded away. She then trades the Big Deal for a Super Deal door and ends up with $20,000 plus the Big Deal, including "the car that just wouldn't stay away".
I don't know if this is "luck" or not, but (at least) two contestants have lost on WoF because they didn't know how to pronounce foreign words ("Milan" and "concerto"); it's painfully obvious that what they're pronouncing matches the spelling, but the producers say "no" both times (and one was an end game).
A contestant on The New Treasure Hunt wanted to take box #1, but changed her mind for some reason; at the end of the show, Geoff reveals that box #1 had the $25,000 in it.
However, the worst luck seems to go to those unnamed TPIR Home Viewer Showcase players who hear the price, realize that's what they entered, and then hear the dreaded words, "There was a tie, so we selected the winner randomly".
(And did more than one person on TNTH keep the money when there was $25,000 in the box? I remember one win and one "keep the money" in the first season, and the two (maybe three) women who chose the $25,000 box always kept the box.)
-- Don