As far as legal blade length goes for me.. I dont agree with them, not even a little bit.
I still carry relatively large blades.. although, i always have the smaller knives easier to access. That way, i can keep my big boy under wraps unless i really really need it.
9 times out of 10, simply pulling something (be it knife or gun) is enough to stop someone in their tracks.
If you think about it, someone who robs someone does so not wanting to get hurt, or be opposed. They want to get what they want fast, and with no struggle. Then get away.
So, when you give them a very very good chance of getting stuck, splayed open, or shot.. they will back off. They most likely dont think $20 is worth death or serious injury.
Now there are exceptions.. so you should NEVER draw without the intent to use.
I have pulled a knife successfully before, but i wont get into that.. stuff like that tents to bring out the politics behind it all with me.
AND on the EDC thought, Got myself 3 more today :P
They arent meant to be concealed, just belt carried.. but I found a way using adjustable bands of 550.
So, now i have 3 short spike style knives that are VERY rapid deployment, followed by my medium sized Karambit neck knife, followed by my Gerber buck knife in my boot.
5 knives in total, if im wearing my belt i will also carry my brass knuckes. because technicaly.. its a belt buckle :P (its a loophole in the law here)
(The spikes are duller than a hammer on the edge, but have a VERY sharp point, the Karambit and Gerber, are as close to "razor" sharp as i dare get a knife without sacrificing edge retention