Other mistake: Marsha Mackenzie is supposed to be competent with certain aspects of men care; she comes from a wealthy family and she has been taking care of the men in her family all her life. And Magnum does show up at the Kamehameha club with a nicely done knot on his tie. When we actually see the actress tie that same not metaphorical knot though, it's very clumsy, crooked and differs in between shots (it's also done on an unbuttoned shirt).
Magnum, P.I. (1980)
1 other mistake in I Do? - chronological order
Starring: Tom Selleck, Roger E. Mosley, John Hillerman, Larry Manetti
Revealing mistake: One of the party guests opens the door of the fridge and you can see behind the set instead of looking into the fridge. (00:32:40)
Higgins: How fiendishly deceptive of you, Magnum. I could have sworn I was hearing the emasculation of a large rodent. To my great surprise, I see the sounds are emanating from what I thought was a harmless musical instrument.
Magnum: Cute Higgins, real cute.
Higgins: Why Magnum? Why do this terrible thing?
Magnum: Higgins, I'll have you know I used to be very good. I was the second best sax player in my High School band!
Higgins: Well, how many sax players were there?!
Magnum: ...Anyway. I just saw this in a pawn shop window and thought I'd like to try and get my chops back.
Higgins: May I suggest that your "chops" are irretrievable.
Magnum: Higgins, did you come here just to abuse me!? (00:05:25)
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