Then you can't complain when the fence prematurely falls down and the guy is long gone.
Most county ordinances for fences are so involved you really do need a licensed contractor just to understand the regulations so your home owner's insurance will cover your liability.
I don't condone the over regulation of construction, but when something dire happens even many posters here will clammer for more oversight and try to make it someone elses responsiblity.
I may be wrong, but I was under the impression that the "borrowing" of these licenses in CA was extensive?
Maybe I'm becoming more of a libertarian than I thought because the older I get, the less government seems able to accomplish even the simplest of tasks in my behalf.
Whatever they touch costs me more and serves me the least. If I hire someone (recommended by friends) to work for me I accept complete responsibility for the outcome. This has served me well in the past and I see no reason to expect less in the future.
Government is NOT my friend nor my protector.