What holds those from blowing away or do they drive stakes into the asphalt?
Recent tent design supports the tent with flexible aluminun rods curved to form the tent contour and putting the entire fabric structure including the floor in tension.
The contents inside on the tent floor must be adequate to resist wind when on concrete or asphalt.
In San Francisco, I would think there is a progressive women’s group of volunteers that go round offering free tie downs
They weight it down with their sh*t.