There are any number of plane spotting sites, frequency sites, live tracking of ATC and message boards where people gather to track aircraft. This is independent of truly bad players and how they (and we) do it. You've been around enough to know that people that truly don't want to be seen traveling or have a critical role don't travel in obvious ways.
There are things worth hiding and there are things not worth hiding. When OPSEC matters it truly matters and I'll be the first to suggest it not be discussed. In this case this isn't an OPSEC issue. It's a big jet on a ramp that didn't arrive or depart in the middle of the night.
Back at Whidbey in 92/93 there were lots of goings on in the middle of the night. It was a real OPSEC issue and it wasn't discussed, even among those of us read in to that program.
Same scenario for a lot of work we did out of China Lake - specific flight times and such for OPSEC. If it shows up in the middle of the day it isn't a big deal.