It's Will Smith, he's the president, and he just got finished dealing with a one of his super-cute children acting up, but actually doing something noble (but getting in trouble at school for it). Upon seeing the swarm: "Aww helllll naw"
There are actually already physical barriers throughout the governmental parts of Washington DC to prevent this sort of thing. There are permanent walls, blocks, and poles along the edges of the roads (often well-integrated into the architecture,) and raise-able barriers built into the road surface at intersections. Ain't no cars running over our president!