Well, if I want to dream big, this would be my scenario for POTUS closing down DC for the funeral:
GHWB was given a day to choose his way out, but POTUS told the family the day they could announce it and the day they had to have the funeral. D5
We get our emergency phone call and drops to prepare and stockpile.
On the day of the funeral, many muckety-mucks are not in DC, but at their homes, because DC is shut down.There is a knock on each door and they are all escorted away in handcuffs. The rest of the derps still in DC don’t even know it happened. A few of them are arrested also, but very quietly. There is a bit of upheaval in DC but nothing like what would have happened if all the derps had been there. All the media are at the funeral, so they miss most of the excitement.
A quiet, orderly cleansing of DC.
{{{Melian awakes from her very happy dream.}}}
Melian, your scenario reminds me of the scene in the second (?) Godfather movie where Michael Corleone is asked to be godfather of his sister's child. While they are at the church, for the christening, the prearranged (by Michael Corleone) murder of all the other mafia don's commences.