What is a "Sacrifice" bonus?
Solution 1:
The sacrifice bonus is awarded solely for being eliminated by another player. Self inflicted deaths, or ones caused by the environment, do not award this bonus.
Sacrifice points are mostly there to help maintain equilibrium, and potentially allow any player to access elite units or heroes without needing to score massive kill streaks to be able to "afford" the upgraded units. While relying solely on this source of income is not terribly efficient, being able to access an elite may be just the thing to snap a death streak.