a lawyer or a LEO.
Here's my story: moved to San Diego 3 1/2 yrs ago. Called the San Diego and La Mesa police departments to find out what's ok here. Basically, fixed blades, of any length are ok, as long as there are not conceilled (spelling-sorry). One LEO from La Mesa went so far as to say that I could walk down the street wearing a "broad sword" as long as it was visible.
As for folders, any blade length is OK, as long as it is carried folded, not in the open position. Some areas of California, like LA and the Bay, do have laws / codes for what length of blades, carry, etc for within their city limits.
As for Carlsbad, I don't have a clue. North County (Carlsbad, Escondido, Oceanside) may be different than down here in S.D.
La Mesa is about 20 minutes from downtown S.D. out in the East County, we've since moved to Spring Valley, a little farther out from S.D. Same rules apply.
I carry a sebbie or a mini-commander clipped IWB or in the front pocket, never had any problems. California has wicked guns laws and liberal government, but knife laws are still ok, so far.
We transfer to Oklahoma in 3 weeks, can't wait !!
Any questions, drop me a line.
Steve