Well, I don't know whether it would actually work or not. I suppose it won't seriously scare anyone. :1orglaugh But it would definitely make me chuckle, if I'd find it on my car. And I rather care about a note, that makes me smile, than about a note, that angers me more. You know.
Oh, trust me, it would take a lot more than an off-tuned girl to upset me - I did find it rather funny, though I admit I had to turn it off after a few seconds, as my vision was becoming blurred, eyesight growing fuzzy and ears bleeding.