We used to augment the SS regularly in the DC area for Presidential and foreign dignitary events. One in particular I did was Clinton’s Victory in Europe anniversary speech in 1995, which was done on Summerall Field on Fort Meyer on the VA side in DC.
SS came in well in-advance, issued out lock-down restrictions for all windows facing the field, counter-snipers set-up on all the roofs looking at any angles a shooter could use, our normal unit traffic was moved to the rear of all the Company buildings in our Regiment, vehicle traffic was cut-off, etc.
I had to do late night guard duty patrolling the field to make sure nobody set-up in advance in the night.
SS recruited from that unit as well, and I’ve known a few SS agents over the years who were assigned there. Background investigation for that line of work is at a different level.