Daily Beast has a slideshow up of famous people recounting their casting couch horror stories. None of them says that they aceded to these requests--only that they were made. Which is sort of a mystery. Do directors just make nonstop passes, all of which get turned down? Are people who turn directors down more likely to become famous?
I suspect the answer is "survivor bias in the sample": people who have given into these requests are unlikely to mention it. Even Hollywood reporting, it seems, is subject to fundamental statistical problems.