bikeforums thread explains that it is trivial to pick a
cylindrical-key Kryptonite U-lock in a few seconds with a Bic pen. One
poster provided a movie (mirrored by Engadget) of how quick it works.
The ten-page thread turns out the way you expect — lots of people
upset that they were counting on this lock to protect their bike, some
others reporting thefts in their area where the U-lock was left locked
on the pole and the bike removed, lots of people angry that whoever
discovered it went public, and so forth.
The people who are angry about it going public haven’t thought very hard
about the reports of bikes going missing around an “unopened” lock.
It’s a little physical-security microcosm of the full-disclosure debate
that comes up regularly in the data world, and it’s a particularly clear
example of how things work out. If you have a Kryptonite lock, are you
thankful that someone broke the news, or are you annoyed because now
you can’t use the lock alone anymore?
More practically, if you use a cylindrical-keyed Kryptonite lock, this
would be a good time to start locking up your bike with two locks.