The term originated from the fact that in the beginning of the
subspace's lifespan, ships started with a negative
bounty, meaning that if you
killed them while they had -6 or so
bounty, you would actually lose 6 points and your
stats would take a severe hit (for victimising those
weaker than yourself!). However, this was greatly abused by players who decided to barrel into top players as a neg to ruin the records of those
other players, not to mention the fact that they just keep running into
minefields and newbies couldn't seem to ever get above -1 bounty by
greening themselves up.