WTI (West Texas Intermediate, the one that went negative) is already settled at a specific place: Cushing, Oklahoma. Unlike with Brent Crude you can't just drive a tanker up to Cushing Oklahoma. So if you buy a WTI contract you are promising to take delivery of 42,000 gallons of oil there...it's the nature of the contract that there's no way around this.
Right, but the reason it went negative is that there was no place to store the oil (demand for storage went through the roof because demand for actual oil plummeted). So that if you held one of these contracts, you had to pay someone to store your oil (directly or indirectly, if doing a cash-settled contract). If the people in the article did cash-settled contracts they would have been in just as much trouble.
