I doubt if companies will ask for login details. The only case that should warrant that is if one is already an employee and is being tried for a criminal offense against the company, like embezzlement. Even at that, giving out login details will still raise eyebrows.
That said, the evil people do online is unbelievable. Most believe it's faceless and they can do whatever they want until nemesis catches up with them.
Well yh that's true. People will always try to be mischievous when they think no one is watching.