Big ups to UB! I would like to say I have been reading many of your post and although I haven't read that many I can already tell improvement from the knowledge you given. Thank you.
I know this thread is kind of old but this may help anyone who comes across it further...
If anyone is still worried even after FYIcool2's post I can assure you would die from lung cancer far before any adverse effects from the paint. A 100lb person could smoke 5 pounds of weed grown in these containers every day for 100 years (easier math) and still would have well below any harmful exposure amounts even if calculated with the most generous absorbance by the plant.
The main reason why the copper pesticides/fungicide are dangerous is because it can be directly absorbed through the skin. Secondly the ___-acides are in much higher concentration relative to the concentration in the paint, and they only have low sperm count from this high exposure. Lastly, and as stated previously the copper is suspended or "locked" in the paint and is not absorbed by the plant and even if it did manage to scoop out a tiny bit, it still would do nothing, refer to first points math.
I would also like to point out you can make your own for only slightly less than they charge. I found the recipe, which is 100g Cu(OH)2 per 1 liter of latex paint. There are articles of the effects of of spinoff on the plants in which they disclose this. I've found several laboratory suppliers that sell this but the lowest i've found was 500g of pure (94%) Cu(OH)2 for about $75, or 100g for about $50.
I do have one question for UB or anyone else who has been using this. I don't think there would be but, have you noticed any thinning or need to reapply after time? thx.