Regular players are worse than bots right now. A good 95% of the players I encounter in the game will killsteal, while the bots will just run away. When asked to stop they will either repeat the request back as a taunt, or tell you to change channels/leave the area.
Killstealing is an issue right now because the game grants most of the benefits to the player who deals the final blow to monsters, rather than to the one who did the most damage.
I strongly suggest changing it so that quest credit (including adventure logs and missions) be granted to the player who has the loot rights when the monster dies. That way if anyone does kill steal, it will only be helping the original killer as they will unlikely receive any benefit from it.