well, the internet is forever, and I responded to the comment as written. Even if you apply your comment only to schools, it is also incorrect. Such violence has been one of the only areas that has been increasing, and it has been steadily increasing (in the US) since long before ZT policies were enacted. The most notable jump in school violence (and mass killings overall) started around 1970. Zero Tolerance policies didn't really start until the early 1990s. The only *causative* factor I am aware of has been the mass publicity the killers receive. Other causes have not been proven (as of my last bit of research on the subject in 2016).