John Hardly, I doubt that most of us (or most of the audience) can tell without an electronic tuner.
Peter, you might consider adding a little "holster" to your guitar strap, as a place to securely keep the Shubb handy. Some straps with a "pick pocket" might work that way.
sophocleese, better yet tie the capo to the cat, then when you need it just call and the cat will come, right? (Yeah, when pigs fly! BG) The dog Mooh mentioned would come, but you'd better want the capo liberally moistened with saliva--if you can get the dog to let go of it!