And I didn't say anything about this having to do with policies of companies. Regardless of whether you have policies in place or not, doing what you suggested without any counsel is a very dangerous way of losing your job. Companies will make it very easy to fire a person who costs them a lawsuit (and the subsequent negative PR).

> My intuition is most companies don't provide the feedback

Your intuition is probably right, but it doesn't mean that people who DO want to give feedback should all of the sudden ignore sound advice. Bad HR teams who don't want to give feedback will always use legality as a shield for an excuse, but that doesn't mean that good HR teams who are also taking legal advice are not interested in doing so. As many people have cited in this thread - the long term effects of giving feedback to rejected candidates (they tell their friends, they come back later, etc) are numerous, but the downside risk makes it very difficult for any HR team to make this investment.