Should they do it? I believe they have a good case to but hey, I'm one of those horrible socialists you've heard about, complete with union (well RCN) card of my own, you'd need to make up your own mind. In my humble opinion though "they work for the military and the military haven't had a pay rise" is a bad start.
See, as one of those nasty capitalists, I do find it irratiting when organsitations and groups want to hang on to the coat tails of the military, are quite content to take whatever kudos they can get from the association of contributing to the defence of the country, but then in the next breath are happy to stamp their feet when they don't get their own way. If we have to put up with contractorisation as part of a one force concept, fine, we will. But you are in or you're out, you can't pick and choose.