It can actually end up unwinding your tax (or regulation) -- If the people rushing to buy up the supply to simply store them off-line happen to cut off people

It can actually end up unwinding your tax (or regulation) -- If the people rushing to buy up the supply to simply store them off-line happen to cut off people who need them for what are sensible and essential reasons, you end up with a litany of cases of the tax causing problems paraded about as it comes into effect, and it ends up repealed or undercut because of political pressure. (Usually 1-year window extended because "we need more time to phase it in" and by the time the second window would close, it's gutted.) It's not just that it can end up counter productive in the short term, it's that it can undercut itself as a law as well by destabilizing a market that usually has low, but important volume.