Construction deficiency ? VW Up – Seat Mii – Skoda Citygo !?

Good evening, I’ve been with a friend for a few days looking for new companies cars. (Small car) As a body Bauer I think I’m probably the first choice for this job. The decision was almost clear, namely a model of the current VW series: Up! – Mii – Citygo. Now to the problem, with all three models, which are identical of the basic structure, I noticed that there are two indentations in each of the two rear wheel boxes. are cavities or recesses in the wheelboxes potential rust stove, because there will inevitably accumulate moist dirt and especially in winter salt. Now, of course, I do not recommend to my acquaintance to choose a vehicle series that will probably have considerable rusting after the first 5 years !? Except of course, that I do not know the deeper meaning of VW for this initially obviously construction lack. What do VW think about it? Why do you think VW Is there no reference to these entries in the respective vehicle brochures and their benefits ? Does VW not break the business if it conceals the benefits of these entries to the buyers !? As a potential buyer, I have to assume that these entries are only useful for the purpose of promoting an early new purchase because of rusting.