As people see a powerful technology and philosophical value system originally developed to promote the self-determination and inclusion of individuals students with severe disabilities applied to and having impact on the broader school population, they wonder what the outcomes will be. In this article, the authors reflect on two issues: (1) the sequence with which schools implement school-wide positive behavior support (SWPBS) (or the "assumption of verticality"); and (2) the potential for SWPBS to legitimize a new continuum and new labels for students. The authors stress that one must be sure that in SWPBS, no child is left behind. There is a need to analyze the function of one's own behavior as one acts and reacts to new applications of a technology that started out with students with severe disabilities and that may now be in danger of omitting students with severe disabilities from the dialogue. The success of SWPBS may also be tied directly to how good people are at applying their knowledge and skills (i.e., understanding the communicative function of behavior) to their school leaders, their researchers, and their colleagues in related fields. (Contains 2 figures.)