I do this to six-year-olds all the time, except instead of "I love you" I say "I'm stupid and I pee my pants!" If I'm lucky they'll look confused and not know what to say. More often, though, they just say "Ewwww you're gross!" and I'll go "Curse you, six-year-old!"
The Romeo and Juliet balcony scene took place in the early morning, too. This is from an evil alternate-reality Romeo and Juliet who spend the entire play throwing pithy one-line insults at each other. They both wear goatees.