I hear your words. I am no expert in any job market. For me, this is an ethical question. I cannot see how the answer here can ever be "yes, employers may do this". Healthy and productive relationships are bonded together by mutual trust, not by demands and sneaking about: all relationships rooted on such demands will carry an expiry date- how will the participants ever be able to take such a relationship seriously, when they are aware to the fact that the relationship was constructed on mutual mistrust to begin with?