Is kinda hard to found when a player "suicide" by will, it can die by a lot of ways, and it would return a lot of false positives.
For example in Sacrifice map, a player must die to finish the campaign.
A person can fall from the no mercy rooftop map unintentionally. (who never?)
Knock instant kills by charger maybe can buggy also.
Sometimes people "suicide" to force a map change, like in the Parish final map (bridge) when a player is in the helicopter and to let it fly, who is outside must die or get into the heli, I "sacrified" myself a lot of times while on bridge, because I have someone in the heli already and we don't want to restart the map again.