The police officer being on or off duty is different for they are ALWAYS a Peace Officer and the classification as "Peace Officer" is where they get their power in the CC and NDA so being on or off duty is not relevant.
The Official Secrets act is also different ball of wax because if you are off duty, you still know the information and that information is still "secret", you being off duty doesn't change that. And if you're Reg Force you still are liable to the CSD.
I'm not saying that I go around and do things that IF I were subject to the CSD would land me in trouble, because frankly I don't, nor would I personally mind. But the question is then, If I only get paid when I work, and If I am subject to the CSD at all times, and then I am liable to follow lawful commands at all times, Do I then get paid if for whatever reason I am walking down the street, in civies and not working class A, B or C, and a WO knows me and shouts an order out to me and I follow through with it? (I am using the "I" and "ME" not as me personally but as reservists in general) What about the benefits and medical coverage, is it then going to be on par? While there are mature and responsible reservists who would have no problem being held liable under the CSD and it really wouldn't change anything in their lives, at the end of the day there are young people (Generalizing, I KNOW there are mature and responsible "young" people in the reserve) who could find themselves in a lot more trouble then they need to be, and asking them to be subject to the CSD at all times when they only work 37.5 days a year is probably unreasonable.
I think the part when is says "Serving with any unit or other element of the regular force....." is meant by "Serving" as in when you are actually being employed on a Class A day, or a class B or C contract.
