Yesterday as I refilled my Nathan, I noticed that I had spilled a bit on the counter. As I picked up the bladder to wipe it off, I quickly discovered the problem. It had sprung a leak. This is my second Nathan hydration bladder that has leaked (they both leaked on the side seam). The first was replaced by Zombie at no charge (it failed in the first few months of use, great service from Zombie). I think this one was replaced last summer regardless of that, this time I will buy a different brand. I have a 50 oz camelbak bladder that has lasted for over 5 years so I believe I will order a 70 oz camelbak.
Well, at least this mystery is resolved and I now have one less thing to worry about for FANs, except it does remind me, was I planning on wearing my vest there? Oh, great another thing to think about ;-).