Employers Asking for Facebook Passwords

I believe that employers don't have the right to ask an employee for their login information.  Being that Facebook is a social networking site and the site is based around people posting their opinions about any and everything, if the employer has a problem with their employees being on Facebook then there should be restrictions saying that while an employee is working they are not allowed to view any other sites that aren't job related.  If an employer asks for login information, I don't think that it should be mandatory that you have to give it to them.  If the employee is worried about that what they're posting on Facebook is being viewed by their company then I would recommend to try and not post problems that are work related to be viewed publicly. If the issue is a recurring problem, then I think it would be a good idea to start looking for another job.