Here are 2 ways to kill lowbies as a hunter.
1. This also flags them. What you do is tame a pet that is around the area, for example, if you are in the Orc and Troll starting place, tame a scorpid. Make sure you are flagged. Now use Eyes of the Beast and move the scorpid ( any monster from that area) to around the person. They should attack it, thinking its a scorpid, and it will hit them for over 50 damage AND flag them for PVP.
2. This second way is if they do not buy your Eyes of the Beast trick. What you do is, with PVP on yourself, drop a snake trap that an NPC will walk over, perhaps a guard. The snakes will kill the opposing faction, even if they are unflagged.
Have fun all.