Thanks Ty.
BTW, I am in the process of install a valve with lock so someone cannot  easily turn it off.  I will also lock my generator so they cannot access  the control panel either.  I posted about someone turn of my generator  on my 'neighborhood web' mailing list.  Some one PM me about gas smell  near my house after the hurricane.  This email "speculate" that the  person that turn off the gas was worry about a gas leak.  The email did  not admitted that he was the one that turn it off which I guess I would  not either given the damage and lost of life resulting from this action.  
As it turn out, one of my neighbor empty house, and elderly couple who  recently moved to the senior assisted living, had tree fall damage that  cause a small leak on their gas line.
We can planed all we want, but things sometime can really throw a curve  at us.  I don't think anybody can plan for this contingency, trying to  do things to protect their tank/house.  Hind sight, maybe I should.  It  really does not cost much in compare to the cost of the tank, or the cost I went through to disaster proof my tank.  I plan to put a tag at the valve, clearly  state that this generator is for life support, and not to turn off.   Also I will put my phone number on this tag so that concern citizen will  need to contact me if any problem.  This will not stop the maliciously  motivated saboteur  but hopefully I live my life in such a way that I  don't have to worry about this.