Yeah, it can be annoying, like it unscrews in the pocket sometimes. but i really don;t think it is a major issue. I have learn't to do it easily now. just press and twist 
Oh that is a cute little pipe! Hopefully someone knows the battery type.
I recall Leaford reviewing the 601 (I think that's what it was) and saying one of the downsides was getting at the batt. You had to twist that little end off and there was really no where to grasp it. How hard/easy is batt removal on this one?
Lu