One lovely young woman -- Sarah -- apparently wasn't thinking of the key to her heart so much as the key to something a little further south: "A chastity belt key!" she said. I never suspected this Medieval side to her but needless to say I was intrigued. Notes to self: Get to know Sarah better. Bring key.
Two guys knew what it was right away. One of them -- Kory -- said, "Oh, that's a fake handcuff key." Well, they're not "fake handcuffs", they're real, but they're manacles d'amour as the French might say. They are more than adequate for restraining your lover, but they're not really what you want to be using as you toss the perpetrator who is high on Super Crack Meth Angel Dust into the back of your squad car. So I suppose in that sense, yes, they are "fake handcuffs".
The other guy's answer was even better. My friend Charlie, who could never be mistaken for a Lutheran, said, "Oh, that's a fake handcuff key. Here, this is a real one."
It's sort of difficult to make out in this cell phone picture, but yes, as nearly as I can recall from the last time I did Super Crack Meth Angel Dust, that is a real handcuff key on his key chain.