This has happened before in parts of the country where you might not expect it and seems to be a growing trend which the government would rather you not know about. Via Reason, a Kansas defense attorney recounts the turn of events:
I had a jury trial this morning on level 3 possession with intent MJ, level 4 possession drug paraphernalia and level 10 no drug tax stamp.
During voir dire, my almost all white, middle-class, middle-aged jury went into full rebellion against the prosecutor stating that they wouldn’t convict even if the client’s guilt was proven beyond a reasonable doubt — almost all of them! They felt marijuana should be legalized, what he does with it is his own business and that the jails are already full of people for this silly charge.
Then, when the potential jurors found out that the State wanted him to pay taxes on illegal drugs, they went nuts.

