lucky it was just the number plate... thank god you didnt park at the place where some other barbaric ppl live.. u would have found your tyre flat, broken rear view mirror and broken wiper. and yes thankfully he left a note on a paper not a DEEP scratch on the car written NO with some erotic scribblings....
i know this, as all this happened to my friends car which was parked on the parking lot in the opposite side of a home (its public parking space). remember ALL the above mentioned happened to ONE car on ONE night.....
so considering this, you are lucky..... cheers.