Nonthreatening knife for a Traceur

[BrianB]

I'd personally go for a SAK with a pair of scissors on it. Super Tinker or Climber. You can even go patriotic with a Super Tinker, so double friendly whammy: http://www.knifecenter.com/kc_new/store_detail.html?s=VN53342

 

[Locust]

I'd say a Salt 1. I have done a little Parkour myself and eventually plan on getting one for that purpose.

 

[Twindog]

A three-inch blade is a load for Parkour. If you really need a blade that long, I'd go through Spyderco's lineup because they are known for high-quality knives that are thin and light. Maybe a recsue/blunt tip knife would be the most non-threatening. The bigger issue will be your carry system.