OK, so people can lie. Can employers demand that health care providers confirm the data?
Only if you sign a release allowing them to do so. That is HIPAA
No. But they can demand that the employee confirm it. Simplest way to clear up misconceptions about HIPAA is to realize that an employer can ask you for a doctor's note to prove that an absence was medically excused. Most people know that, but for some reason there is a disconnect between that reality and what they think they know about HIPAA.