If properly installed, they should not do that at all. The good news is that ALL the Undercover models now have the most recent knob brackets, they no longer have the little rings that you had to remove to remove the cover.
The Undercover SE-Smooth is a GREAT alternative to a fiberglass cover.
I agree David but these days a lot of guys are trying to save a few dollars and doing everything they can themselves.
Nice looking covers and always have been. BTW..I'm still running the Retrax I got from you in 2005. Still looks good and works great. For my purpose it's awesome.