It would go under the "You may not keep following another player around killing/looting their monsters without their permission," clause.
But I would have to see screenshots to determine whether or not its repeated over a prolonged period of time. Like, (example) if someone hangs out/follows you for a solid hour just to make sure they kill everything you spawn, then that's excessive and punishable. But otherwise, it is allowed in KS-maps. Knowing that, its best to be proactive and try to get yourself and your plants in a low-traffic area whenever possible to avoid that problem.