They are not all suicides. Some of it is constructive homicide  (doing something that is statistically likely to generate the death of another person). 

An example I witnessed was a white male muscular lean build egging a younger guy into jumping across the track in front of an oncoming train as a stunt. My take on the situation was that he was trying to get the guy killed.

In another instance, if an investigator says "dont' jump" to somebody who is minding his own business on a subway platform, is that not a suggestion to jump? An interesting statistic would be the number of suicides by people who were under police surveillance during the event.