I drove home through some torrential rain the other day and was surprised when I got home to see some black plastic dragging under the car. I was even more surprised when I found that it wasn't an inner guard as I suspected but a piece of black plastic underbody trim/cover that hangs down and "protects" the fuel/aircon/other lines and other associated things.

There's aluminium heat shield around the exhaust but there's a bunch of other black plastic underbody covers that have various holes in them. A bad design that when coupled with torrential rain/large sheets of water across the road, and front tyres which displace the water well, displaces the covers (well at least the one on the left side behind the front wheel) from its mounted home.

I managed to rob one of the flat aluminium "nuts" that hold the heat shield up and put that back on one of the captive studs attached to the floorpan, but there's a couple of decent splits in this piece now, and part of it is being held up with tie wire now.

What are the chances of having parts damaged due to driving on wet roads replaced under warranty due to what I believe is bad design? How much should VW reasonably expect me to slow down driving in the rain to protect flimsy plastic parts underneath the vehicle?