Crafting Materials not tradable

I'm curious to see if making crafting materials non-tradable gets the bot farms to stop idling the game. Even though playtime drops have been disabled for a while there are some accounts idling, presumably to get items if they return. Currently there is no plan to re-enable item drops again because of the bots.

I thought about providing heads-up on the main menu about disabling trading of crafting materials some amount of time in advance, but I suspect this would have a more negative effect by encouraging bot owners to flood the market.