A police discovered a swiss knife being carried by a person after doing a random spot check. The officer then called for backup and arrived on the scene were 18 of his police officer buddies.
The knife in question was 5cm long - Japanese law permits knifes up to 8cm to be carried (source).
The knife carrier was questioned for 2 hours and said the swiss knife was used for bike repairs.
More pics of the incident at Akibaos and Akibablog.
Do you or people you know around you carry knifes - swiss or otherwise?