Yeah its terrible the things they nick and you are probably right, it wont be kids. I've had things like the badges off the center caps being pinched (funnily enough when I saw another Mini in the car park missing them, came back mines gone along with the other Mini)
A lad my age nicked every dust valve cap of every car in our village and then did it again when they were all replaced. Police found buckets of them in his bedroom and no reason for why he did it.
Could be worse tho, someone tried to nick my dads grill from his 5 series and then the badge. They managed to get the enamel part off but left the metal and it looked shocking!
It could be the same person, I thought this when someone even nicked the bright yellow minging ones I fitted!