Besides a green road sign that proclaims South City's population to be 65,020 people, there's usually not much to mark the border between San Bruno and South San Francisco.
But driving down El Camino Real today, the border was clear. As a mass of vendors got ready to start selling (legally) fireworks tomorrow at noon in San Bruno, a portable sign at Noor Avenue flashed "Fireworks Illegal in South S.F." as you crossed the border into South San Francisco.
that allow people to set off their own fireworks. As the sign indicates, they're illegal in South City.