Let's not include any professional competitions or world championships. However, I do feel depending on the event that there are TONS of athletes in the Olympics who aren't in the race and know it, but are likely going as hard as they can.
"the trick is to keep losing weight until your friends and family ask you if you've been sick. then you know you're within 10 pounds. if they start whispering to each other, wondering if you've got cancer or aids, you're within 5. when they actually do an intervention, you're at race weight." - Slowman