[JJMcJ]

Often it's more for tax evasion. Beth pays for cars as a business expense.

Bob just happens to have the Cayman Islands as the business location.

Money flows from U.S. business as a deductible expense, to the location out of the IRS's reach.

Or there isn't one Beth but lots of people with dodgy credit cards from banks in weird places. Those card holders indeed get their money in suitcases full of folding money, pay for their "rentals" and so the money flows into legitimate commerce. Bob of course pays for this.