Ive just been telling them no on samples. Past experience dictates future decisions, and i can say with confidence that half- stepping, free sample hounds arent the kind of people i ever ended up doing any kind of meaningful business with. Serious buyers bought pounds as a test, as anyone on that level should know you arent gonna get a good picture of whatbit is unless you have that amount in front of you.
Best way to stop em, stop giving free samples. Period.