To be fair to the government, unless you're selling or holding a significant amount, you wouldn't go to jail. You most certainly wouldn't be put in jail for taking a few micrograms of LSD in the comfort of your own home (or office).
Unless of course, you had said LSD on some kind of substrate, such as blotter paper, or god help you, a sugar cube.
Then the 'fair government' would weigh the entire product, and charge you for posessing that much LSD, which would weigh enough to charge you for distribution, thus sending you swiftly to the nearest PMITA Prison.
Fair enough. Though I suppose my point was, recreational drug use is only illegal if you're caught, and it is incredibly difficult to be caught. The government doesn't really care if individuals do drugs, they just get pissed when people distribute them without giving the government a cut.
The assessment is statutorily presumed to be valid and correctly determined. The burden is on the taxpayer to prove otherwise.
The criminal prosecution for failure to pay the drug tax and the civil tax assessment are separate actions. What occurs with the criminal case, for instance, does not necessarily affect the Department of Revenue's tax assessment.
