All of which means the dealer knows how dangerous/Potent they are?
Do they inform the buyer?
I am guessing no.
Some dealers actually spike random packages to OD buyers. In that game, everybody waters down their product to get as much money s possible, so when the junkies hear somebody overdosed on the stuff from the guy on Baker street, they all run over there to get some, thinking he must not be watering his down as much. Of course he is, he just spiked one package with Fentanyl.