And yes, it's patently obvious that it's at horizon scanning level - the Urban Warrior exercises/experiments would have been blown open if there was a RM or RN Officer on the Red Cell. I live there, and I could have run rings around the "Blue Forces" using the rivers and creeks of Southampton.
I may have said it before, but one of the most spectacularly effective deception ops I've seen (on exercise) was at HCSC during HABILE CORMORANT, where Red were winning the land war, although taking a bit of a pasting at sea.
One of the students was a USMC colonel, and he was a great guy anyway but he looked *exactly* like the stereotype of a senior USMC officer sent from Central Casting: tanned, square-jawed, white hair cut short and flat-topped, Southern drawl... and he had an amphibious task group, and he was running it straight into Beaufort (capital of Verdatia, the main Bad Guys).
And EXCON absolutely freaked out that he was (a) going to smash a brigade-plus ashore into Beaufort and (b) that they'd left virtually nothing to stop him and _this might actually work_ - and so Red stalled their advance on the critical oil infrastructure, pulled a couple of armoured units back to defend the capital, and basically lost the war.
Especially when it turned out to be a feint, the ships were empty, and the Marine brigade were gainfully employed elsewhere in smashing the now-disorganised Red horde. Beautifully done - a combination of knowing the value of littoral manoeuvre, and also playing to preconceptions.
In other iterations of the Theatre War Game, being able to easily move a significant force with its support and supply, 500 miles a day around the blue bits of the map[1] often had a serious (if less directly game-winning) impact: comparing what one of the Red partners could notionally do with their half-squadron of transport aircraft, with what they achieved when discreetly loaned a decent LPD, was an eyeopener even for the OA staff let alone the players.
Or, short version - fear exposed flanks especially when they're rivers or coastline, Bad Guys who do LitM can arrive there in strength remarkably quickly.
[1] I took a sadistic joy, during navigation lessons, in referring to the printed material that represented geographical/hydrographic realities as "the map" just to see steam come out of my instructor's ears - he was a nice bloke but a hardcore navigator.