You guys on this thread are over thinking everything.
These FABRIC liners are installed on most high end vehicles like bmw, mercedes, etc. Not just our 20k cars. They are more then capable at blocking debris and water from harming anything. I do not understand where your guys worries are coming from. Corrosion also won't be an issue as the inside of the wheel wells are undercoated (not that rubberized crap rock guard, they have a technical undercoat) to avoid such things from happening.
If you hit something, go through a big enough puddle, or have an incapable body shop repair something on your car. Yes the clips may fall out or possibly rip the liner. But thats pretty easy to avoid, don't hit cats, avoid 3 foot deep puddles and stay away from shitty body shops.