Interesting thread!
My point of view is that the best defense depends on the agressor.
The few times I felt in danger, I took a Cold Steel Master Tanto with me, in a kydex sheath fixed on my boot (under the pant). Invisible, impressive, solid (it can pierce a car door), and with a small guard to prevent the finger to rip on the blade. The Kraton handle glue to your hand, and it's pratical/pleasant to handle.
For the fan of Platoon, the movie, 1 of the lead sergeants has this knife (upside down on his shoulder). The second sergeant has a Cold Steel Push Dagger. It's also an interesting knife, I think.
But in other cases, when I *guess* I won't meet a professionnal knives fighter, the balisong is fine : lighter, smaller, more discrete, can be quickly drawn...
About the intimidation, I agree with you guys; it depends on who is in front of you. A unexperimented agressor will be scared (often, when there's a risk they quit... it's easier to take the wallet of a grandma') by the bright and agressive aspect of the bali. And by the manipulation too. Of course, a guys who knows how to fight with a knife will immediately kick you in the hand when you'll manipulate it and the bali will fly to the dust... it's about judging well his agressor, his state of mind (determined or scary/stressed). Keeping the manipulation (very) short is a good advice I think.
Summary : a Tanto when you go to a battlefield

, a bali for the street (except very hot streets -- don't go there).
Guillaume
PS: I may have frightened people... I never walk in the street with a knife. It just happened very few times, when I knew I had to go to a place where problems happen frequently.
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