I notice that the lens cap is attached not to the lens body but to the moving element group. This troubles me, as the lens cap protrudes, and thus it is likely to be hit, resulting in a direct impact to the focusing apparatus. It seems to me that with the lens cap removed, the tiny front element is exposed, but the focusing apparatus is better protected. Also, the lens cap does not protect debris from entering the focusing mechanism, only from contacting the front element. Hence, I think I'll forgo the use of the lens cap.
Just got mine and I noticed too that the lens cap is pretty thick being a center pinch style. I was thinking about just using a bare UV filter instead of lens cap. But I wonder if that would introduce some other complications. I was also thinking that perhaps it would help with flare as the ring on the filter may block some stray light. Comments?