thats ridiculous, a lot of cars come standard with painted sideskirts (my civic included) and paint will never flake off unless it wasnt done properly in the first place, if there plastic they need to be keyed up(lightly sanded to grip) and then primered with plastic primer but normal primer should be ok if there not too flexible, this'll then be flat sanded with p1200 or similar to make it nice and smooth for the paint.,., then a few layers of paint and the laquer.,. flat sand again with p2000 this time and then a good rub down(or buffer) with compond and it'll bring up that lovely shine.,, you could also give it a hand glaze but if its only a pair of side skirts you'll hardly notice it either way..,,.,,