I don't know Berkley ( except by reputation), but I do soils and foundation engineering in MD, DE, PA and VA.
Frost is a real concern here, and the minimum detph from the ground surface to the bottom of the footing is 30". Obviously, your frost design depth will be a lot less. This information is easily available from the local Building Official--make an anonymous call.
How much is the permit fee? Is it worth NOT getting one? The other side of the issue is that while she may save a little money, and not have it show up immediately for tax purposes, is that the home insurer may decline any protection to the home owner if there is any claim.
There are any number of books on deck building that take you step-by-step thru the process of designing the footings. It isn't rocket science.
As far as Guard Rails go, according to the International Code, they are to be able to sustain a 200lb force at any point, in any direction. I've seen many that would not.
I can't imagine that the cost of the permit is greater than the benefit and protection it offers--especially since you will be liable if anyone gets hurt on a non=permited structure. Its HER money and YOUR liability--get the permit, and get the plans approved.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags