If the problem is technical, the candidates get their feedback immediately. Either they themselves know they botched up the question, or they are given the clue via absence of a follow up question. The best thing you could due to salvage such situations is to ask what the right answer is. That not only serves as feedback but also signals that you are willing to know.
The feedback you don't get, is almost always about personality. There's no litigation-safe way of saying "Man, you come across as a total douche, I'll pass"
The feedback you don't get, is almost always about personality. There's no litigation-safe way of saying "Man, you come across as a total douche, I'll pass"