No, they should not be allowed to even ask. The problem is that when some people are allowed to give up certain rights for a potential advantage in hiring, then

No, they should not be allowed to even ask. The problem is that when some people are allowed to give up certain rights for a potential advantage in hiring, then it becomes the de facto standard that everyone has to give up that right in order to have a chance. In most industries the employer holds all the card, so that everyone will just go along with it because they feel they must in order to be considered. You're naive if you think the "market" will correct itself such that these types of invasions of privacy are eliminated. When we're talking about people's livelihood you can't expect them to act in such a way that maximizes their rights. They act in a way that maximizes their livelihood, potentially giving up rights that they otherwise would not have. Government is the only thing able to keep employers from having that power.