For me personally, I think the discussion about taxes in this context is a distraction at best. How long before cash is banned altogether, in the name of "making sure everyone pays their taxes"? That doesn't seem like a solution, that seems like oppressing a populace while making them think it was their own idea.

Governments worldwide have been trending towards being more authoritarian, and I see outlawing cash purchases of any amount as an incredibly easy way to begin clamping down on the use of untraceable fiat currency.