the 10 second rule, for those that don't know means that so long as you dealt damage to an enemy within 10 seconds before it dies/explodes YOU get the bounty and not an NPC that may have been shooting at it. It helps the player by lessening the NPCs that can 'steal' a bounty from a player, and it gives you more time to take careful shots. But it can be exploited while you hang back and allow NPC authorities to weaken an enemy, then you swoop in and take the killing blow.