I actually agree, Rationalthought.  16 year olds marrying 60 year olds gives me the creeps.  On their other hand, I've seen episodes of Sister Wives and stories on 60 Minutes about polygamous relationships involving numerous educated, professional wives working mainstream jobs who are obviously exercising fully informed consent.  (even a case of a polyandrous arrangement where the husbands were fine with it).

Still, should the suspicion that some might be brainwashed negate the option for those capable of exercising informed consent?  I'm not sure how, but there ought to be safeguards to protect the truly brainwashed without limiting the rights of those capable of exercising informed consent.

The principle is not unlike physician-assisted death.  Lobby groups worry about the disabled feeling pressure to end their lives.  That's a legitimate concern for which there needs to be protections, but it shouldn't negate the option for those capable of exercising informed consent.