You mentioned the Exercise Square Leg - that had a period of a month between the first transition to war measures and fighting starting. The preamble to the leaked plans for Exercise Hard Rock also talked of months of deteriorating East/West relations. There would have been multiple warnings and indicators.
The Reforger exercises were to demonstrate the ability to reinforce in time of crisis. @Not a Boffin might be able to tell you more. NATO naval strategy was all about securing the Atlantic SLOCs.
I'm not doubting for one second what the naval strategy was. But the majority of the kit for the reinforcements was already in theatre. Have a look at 51°22'13.86"N, 6°14'14.09"E. That place was full of US kit, and it's not even in the US area.
It still goes on to this day. 51°49'54.47"N, 7°18'28.81"E is the Dülmen depot, which the US took over when the RLC left.
Even the UK retains Ayrshire South Park, which conversely, used to belong to the US. 51° 9'44.27"N, 6°23'56.50"E, full of Challengers, AS90s etc.