Whats behind those arches ?

Have you every wonder what happening behind the wheel arches ? All HT81S comes with additional bodykit to make the car wider and look better, however those plastic arches is an extension to the steel body.
On average most of the HT81S are around 10 years olds so what do you think happened to the paint behind those arches ? The photo above show what happening, so what do you think ?
Anyway, the picture do not belong to me, just borrow from a fellow HT81S owner in twitter.