"Please note that you may elect to make payment of the purchase price for this lot in the cryptocurrency Ether. Payment in Ether must be made via a digital wallet transfer of Ether to Christie’s. The digital wallet must be maintained with Coinbase Custody Trust; Coinbase, Inc.; Fidelity Digital Assets Services, LLC; Gemini Trust Company, LLC; or Paxos Trust Company, LLC. Only Ether payments sent from digital wallets maintained at these platforms will be credited towards this lot purchase, and we will not recognize payments from digital wallets hosted at other exchanges or self-hosted wallets. The digital wallet must be registered to you, or, if you registered a bid as a company, then in the name of the company. You agree, upon our request, to provide documentation confirming that the Ether payment was made from a digital wallet registered in your name and maintained at one of the platforms listed above. Partial payments of a lot from multiple digital wallets will not be allowed."
It should be noted that all of these exchanges are US-based and comply with all know your customer and anti-money laundering laws, rules, and programs.
Doesn't mean that money laundering is impossible (US-based banks do it everyday) but it's interesting that they will take Ether but only from an extremely narrow list of whitelisted source Ether addresses.
Also makes you wonder what happens if you (somehow) send $70,000,000 to Christie's Ether wallet from a non-approved address. Presumably they wouldn't touch it and transfer it back but I suppose you never know...
Probably no different from sending an unagreed wire to their bank account? They'll just refund, maybe subtracting $50 for "processing" or whatever.
You go pick up a random painting, or scribble on some canvas yourself. Then get your art appraiser friend to say your painting is worth $1MM.
You then sell that painting at auction to another friend for $1MM. Cash only. Private transaction.
But the cash never actually changes hands. Your friend gets the painting, and you claim that the $1MM of dirty cash you had laying around was instead proceeds from the art sale.
Now there are tons of other examples out there with different methods. But it generally all comes down to selling an object that cannot be objectively valued for an all cash price.
But that doesn't really solve the problem. Now rather than you having to explain to the IRS/FBI how you got that $1M bag of cash, your friend has to. It's really not any better than taking that $1M bag of cash, and using it to directly buy whatever you want (eg. a mansion).