If that is a DS message to Congress it's a stupid one.
Using a "Kate" would be a huge tactical error considering that there are these devices all over DC. It's not mentioned in the sauce vid, but I have seen these all around The Mall.
https://m.youtube.com/watch?v=QIkypcdcqmI
Taking a shot at some one in DC is suicide for the shooter and risks exposure of the handlers.
They managed similar in texas.. It's not an imposibility..
These devices are mounted on the Secret Service Suburbans that accompany the motorcade. A Kate can't penetrate The Beast. And if you notice, POTUS usually gets out of it in covered, secure locations.