OUT OF HAND -- "If you reject an offer or idea 'out of hand,' you do so without hesitation. However, this phrase has several different meanings, the oldest of them being 'out of control,' from the days when failure to keep a firm grip on the reins would result in a team of horses being 'out of hand.'" From "Morris Dictionary of Word and Phrase Origins" by William and Mary Morris (HarperCollins, New York, 1977, 1988). Page 433.<<<

I found above on google; which suggests that to marry someone 'out of hand' means to do so without hesitation; presumably being free of lets or hindrances &c. Probably used as an emphatic intensive for the lack of delay or hesitation. I don't think the phrase as used in songs &c has any further legal or other connotation; but perhaps one of the Mudcat lawyers could confirm this?

Hope this helps, Sylvia.

~Michael~