"I thought detecting was a no go on all military bases....."
Ft. Ord near Monterey, CA (WWII origination, for all practical purposes) has been routinely detected since the 1970s, and no one has cared less (unless you were being a nuisance in some other way, or being st*pid and making holes right in front of a bored MP or something). But for the most part, no one has ever cared. Now is that to say that if ..... in all those years .... that if we'd asked enough high brass, or gone high enough up the chain of federal archies, that we might not have found ourselves a "no"? OF COURSE. You can always find a "no", at even the most innocuous places, if you ask long enough and hard enough.
All I know is that the only federal military bases I've ever seen, where anyone cared enough to really enforce anything, was when it was an obvious historic monument type place. There is one in SF, for instance, that dates to the mid 1800s, where I heard of some guys who got grief. But I mean, c'mon, a little common sense would have told them that.
