Just got an eztest kit and tested the berry flavored oil in one of the carts. Looks like it turned the liquid a very, very light pink. It's supposed to turn red. The redder it turns, the higher percent of thc is in the product, up to 20%. So if it turns bright red, you know you've got something with at least 20% thc in it. The very, very light pink tells me there's barely any thc in it. I already knew this by how weak it is. And the oil is very tan. You can tell it's an extremely cheap bho. People should keep buying from him though. I don't really care.
The glycerin and flavoring in the vape mix will 100% interfere with the Duquenois-Levine reagent, the mixture used in the test here. This method is wildly inaccurate and many different substances can induce false positives.
I'd get actual testing done before calling someone out like this. All this proves is that the carts do in fact have THC in them, the shade of color can be influenced by a huge number of variables.
I had a great time with the cart I ordered. Got me very high and seemed to last forever.