Speaking from someone who had to embarrass someone in a similar way once, I wouldn't doubt that this wasn't the first time the boy expressed his interest.
A lot of guys out there, for SOME reason, think that "not interested" means "go bigger and bigger until I'm FORCED to be interested." Had a guy (who could have been a good friend), ask me out continuously, with me turning him down each time. Finally reached a breaking point when he uploaded an incredibly embarrassing youtube video of himself asking me out and posted it on facebook. It was incredibly mortifying. I defriended him, told him to leave me the fuck alone when he called, and never spoke to him again.
This poor kid obviously means well, but I'd bet any kind of money that this isn't his first time going after that girl unsuccessfully. She's was probably at a breaking point. Guys ALSO don't take into account how extremely embarrassing these "grand gestures" can be for the other person, especially if the interest isn't reciprocated.
So what you're saying is the grand gesture only works if it is reciprocated. Which is obvious. If the girl liked him it would have beeen "awww...that's so romantic" by the girl and her friends.