that's true, you have to take it off for a dock charge + if you use a lanyard you can't remove this cover easily as it attaches the phone to the cover, securing this corner - DEFF mentioned earlier also make nice rings too!.
anyway it's so thin that it can almost be pushed all the way in the dock. dremel both?
ah, if you plan swimming pool movies, better remove cover and go naked (your phone ^^)
adding a case create gaps for drops, tends to retains water on the back, +you will soon have to take it off to dry it well