Jena, a 12 year old girl , sucessfully demonstrated bumping a medeco not once but 3 times at Defcon 15.
Its now proven medecos are prone to being bumped.
Marc Tobias has also released a video and pdf report showing how most medecos can be bypassed in less than 30 seconds, not by picking or bumping but ..... by exploiting a major weakness in medeco locks.
in.security.org has the videos and pdfs documenting these.