Your 3-piece spoiler's center piece is spring-loaded and can bounce right back in place, however, the left and right sections are not, which means they could rip off altogether if you hit a bumper block or curb.
These black, ABS plastic brackets take the brunt of a bump and prevent bolts from sliding through, keeping your spoiler securely in place. Kit includes one left and one right bracket and installs easily using existing fasteners.