I am in the PRes in Halifax which is fairly used to a military presense thanks to the Navy, Airforce, and Army (Dockyard, Shearwater, Amouries, etc, respectively). Anyways, it was always made clear to me that you DO NOT wear your uniform unless you are being paid to do so. With the exceptions being the one stop rule on the way home or to work.
I myself, and other in my unit always head out to McDonalds, or Wendys or the like for a quick bite to eat after our parade nights and then head home.. But I would never think about wearing my uniform to the bar or a sit down restaraunt even.
Also, at my university I've seen quite a few people in class in Navy uniform. They're always wearing it properly and what not, so I always assume they head to work right after, or were at work right before and don't have time to change.
I guess it just boils down to it's a work uniform, and when you wear it you represent a large organization by default, whether you like it or not. So it comes down to pure common sense. Just the same as when I worked at Blockbuster, I'm sure they wouldn't let me stand drunk outside the store in my uniform telling customers to F off, even if I was off the clock
Common sense, that's all there is to it.