From my recent research there is occasionally a candidate asked for their Facebook password. This is an illegal question to ask I will state right now. From further research it is being used as a test to see if you'll answer it in a few cases. In at least one other it was for corrections officer position which could be an understandable one, maybe. In the vast majority of jobs you can probably expect not it to be asked this. It's just something you need to be aware of as you set up interviews. I would probably state that I wouldn't be comfortable with giving them that information.
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