I often use an alunimum-handled Jaguar M4 Balisong as a Sgian Dubh, it stays put nicely in my sock top. Never had any problems here in MN, (I think they are verboten in the city limits of Minneapolis) I once loaned it without incident to a Sheriff's deputy so he could open a box. Doesn't surprise me a bit that it is forbidden in California.

I was privileged to have learned some Balisong techniques directly from Filipino martial arts master Dan Inosanto when he was in MN, my most recent knife training was in the Filipino Pekiti-Tirsia Kali method.