They can. It just gets reported to FinCEN, which might attract unwanted attention. The same applies to buying a $200k lambo with cash, which has to be reported to the IRS[1], on top of being registered with the state DMV.
Some people buy used hot rods on Facebook Marketplace for around $100k, then trade them in to a dealership. They claim they only paid $5k for the car and their labor increased the value to $100k, then use that trade-in value to get the car they actually want.
They can. It just gets reported to FinCEN, which might attract unwanted attention. The same applies to buying a $200k lambo with cash, which has to be reported to the IRS[1], on top of being registered with the state DMV.
[1] https://www.irs.gov/businesses/small-businesses-self-employe...