It literally happened to my wife the other day - she was asked if she wanted kids. HR could have warned them not to say that. Apparently they did not.
The same companies that don't give a shit about this don't suddenly become more legally risk averse when it comes to feedback. They aren't genuinely worried that your programming test feedback might say your algorithm was too jewy or your knowledge of data structures made you look pregnant. Theyre just afraid that your feedback will make them look stupid and don't want to admit it.