Sure. But they usually do so out of noble purposes such as taking the blame for a family member or being a planned fall guy to hide a bigger crime. None of those apply here.
Most of them do it due to mental illness. Some of them do it to protect family. And some of them do it because their lawyers advise them to due to overwhelming evidence that is either framed or circumstantial. And then you have some that do it to avoid a lengthy legal process of something worse - which IMO is what we see here. Ronaldo seems to have admitted it in exchange for getting the victim to sign the NDA. Which he could easily have done to avoid a lengthy legal process and media circus that would damage his name and brand, even if he was ultimately acquitted.