There is no point trying to get afk farmers to understand as they already have the mindset that as long as being afk + companions doing something which is AI and auto is technically legit, they can do that. IMC does strongly discourage afk farming though.
What we can do is to propose ideas and solutions to solve the problem.
Suggestion: Introduce an affinity mechanic to all classes with minions/pets/companions. (Falconer, Hunter, Sorcerer, Necromancer and in future Shepherd)
Pictures speak a thousand words, let me put up a few scnshots for this.
Affinity bar looks something like this, it represents the affinity of the companion(s)/minion(s) to the player.
How it works
A moving pointer will slowly move across the affinity bar, it takes around 30secs for the pointer to move from the start to the end before repeating itself.
The player can at any point of time, press a predetermined key (can set with hotkey) to register the affinity point.

If the player presses the key at the green zone, all companions/minions will gain an attack/def and attack speed boost buff for the next 30secs. Land on the yellow zone, nothing will happen. Companions and Minions do the same damage as before.
Pressing the button on any other place besides the colored area will cause all companions and minions to deal NO damage for the next 30secs.

The colored zones will be randomised every 30secs so as to prevent players to get into the habit of pressing the hotkey in a rhythmic fashion.
What this suggestion does:
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Enables companion/minion classes to have some boost in the damage department. (They do need it as compared to the pure damage classes)
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A slow pointer with next 30sec buff ensures low learning curve and easy for players to pick up
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Non intrusive which changes very little of sorcerer/necromancer’s skills
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Makes it extremely hard for players to afk farm or macro as position of colored areas are randomised every time.