There’s a wonderful item in Bruce Schneier’s latest Crypto-Gram that captures the balancing act between security and convenience/usability. The issue is how to bear-proof trash cans in Yosemite. The story isn’t well sourced, but it’s one that illustrates a point even if the tale can’t be verified. My favorite quote:

Said one park ranger, ‘There is considerable overlap between the intelligence of the smartest bears and the dumbest tourists.’

A tangent – I have it on good authority that the most dangerous animal in Yellowstone (besides H. sapien) is the Bison, filling the same niche in North America as the hippo does in Africa: very large, shockingly fast, single-minded people stompers.