They don’t want the Russians to know they weren’t watching.
Seems a more likely scenario than some others.
Or, they don't want any potential foe to know how well (or not) they are able track such events. Ties into missile defense.
“They dont want the Russians to know they werent watching. Seems a more likely scenario than some others.”
How is that likely?? There were not less than a dozen sensors watching that one come in.