"As an employer I think it reasonable to ask how an applicant's spouse
and/or family might react to moving long distance. "
That would hold true if you were the employer and transferring the
employee, perhaps. But as a prospective employer, I question the
appropriateness of knowing the applicant's marital/family status. When I
interviewed people, I did not ask about family. I did not look favorably upon
candidates that volunteered this information that I considered
inappropriate. When asked as a candidate, I would say that everyone was
excited about the possibility, and sometimes I would say that the "everyone"
consisted of a mix of four-legged species.
Isn't equal opportunity about hiring the candidate and not their
spouse/kids/mother?