I've not tried it myself, but, have you tried setting this?

results = {},


Alternatively, instead of a fluid, how about you instead use an item with a probability of 0?

results =
{
{type="item", name="copper-ore", amount=1, probability = 0},
},


Like I said, I've tried neither of these, but ...

I made a forum account just to say thanks for this, so thanks!

Edit: This actually causes a crash with DyTech installed if you mouse over the corpse to gems recipes from an assembler. I fixed it by changing

results = {{type = "fluid", name = "water", amount = 0}}

to

results = {{type = "fluid ...