You will not solicit login information or access an account belonging to someone else. — Facebook Rights and Responsibilities, Section 3: Safety)
Violation of the above can result in a company or the interviewer’s Facebook account being suspended or even deleted.
What Employers Need to Know
Given that many companies and government agencies have considerable investment in their Facebook presence, it makes little financial sense to put that investment at risk by demanding access to job applicant Facebook accounts.
What Job Seekers Need to Know