I noticed they all have guidelines that the creator says yes/no to.>Individual>Non-commercial>Commercial>Processing
What's allowed/disallowed varies with each one. If "non-commercial" and "processing" uses are okay'd, I'd say it's not too
bad, as long as whatever product is made doesn't get widespread popularity or anything.
Still, you're right. For the reasons you stated, it'd probably be for the best to just ask them directly and personally if it's alright.
I'd also like it if a farmer artist made one of these, wonder if any would be interested.