I dont have hands on experience, but just ordered one. As far as i can tell, the 'shield should give you enough "give" to allow the clickwheel depression. I recently had a ipodwrap, similar to the 'shield (no lifetime guarantee) on my clickwheel ipod and it worked fine, in fact, it made the clickwheel a bit more exact.
I ordered a 'shield for my wifes "soon-to-own" nano as well as my soon-to-own vPod.