[runnerup]

> then ban cash in the mail too

I mean, yeah this is already done. Over $10,000 requires you to file a FinCEN Form 105. The point isn't "you can't send money" its "The US government only wants to allow systems to exist in which it knows who/what/when/where about any non-trivial sized transaction."

If there's an auditable/subpoenable record, they're happy. If not, they're not. Right now they're "not happy" about XMR. Some day they'll ban it.

As for ETH/BTC<-> XMR they'll probably ban that too. Not from a technical perspective but more like "if we catch you sending ETH to that Russian XMR exchange we'll prosecute you."

[notch898a]

Honestly banning cash would be one of the easier things to do, but I don't think what you've said is necessarily true.

I cannot offer legal advice here, but my understanding is if Bob in NY has the fantastically idiotic idea to send $100k through the mail to cousin Suzy in CA, he wouldn't be violating in laws by not filling out the 105 or IRS 8300. He's not engaging in a trade/business and the money is not leaving the borders.

[runnerup]

I meant internationally, domestic cash transactions don't currently have reporting requirements per se. Most domestic cash mails would eventually reach a magnitude large enough to meet a reporting requirement for sales tax, 1099-MISC, gift tax, etc.