Also, what happens if both parties agree to a salary outside of the bound during the interview. Is the employer bound by that number? I am guessing there is no mechanism that would enforce it.
I imagine nothing happens. It's just an indication of what the company is thinking they're going to pay. This helps people who are bad negotiators from getting into trouble; "And what are your salary requirements?" "....uhhhh... 60k?" "Awesome, we were thinking we'd have to pay at least 100k"