I just had this random thought while writing another comment about why so many soldiers are in place. We know in the past year (ramping up after the election) the President has made sure to put his own loyalists in charge. He has had multiple secret meetings with the joint chiefs, likely to brief them on the evidence and the coming events. But the possibility remains that some part of the chain of command - either because of MSM brainwashing or because they are loyal to the Deep State - decides to commit treason and remove the President by force. An example would be Tiny Dog Mattis meeting with Brennan to discuss "difficult choices" they will have to make if Trump refuses to leave the White House. They openly admitted to it in the papers. Obama went on a talk show and "joked" that they might have to send in a Navy Seal team to get Trump out. These are people no longer in power, but who knows how many allies still on the inside they've emboldened with their rhetoric, or are even still in communication with.
Maybe just having so many soldiers in place is meant to act as a deterrent against any uppity Generals who think they can depose GEOTUS. Whether or not he's actually in DC or not at any particular moment is irrelevant. It's about territory and control as much as it is one man. (and really it's Congress that we need to keep under control to stop them from giving the oath to someone else)