Disclaimer: I worked for the hedge fund at the time that bought Amaranth's holdings for pennies on the dollar. Was supposed to be a joint buyout with JP Morgan Chase, but Chase couldn't calculate the risk in time before closing and left us with all of the eggs in the basket. We ended up making a killing on the deal as we had the assets to weather the margin calls. I still can't believe anyone gave B.H. any money to trade with after that, but someone did...
Back in 2008 when oil hit $150, it was due to a single trader. Needless to say, everyone in the industry was pissed at him afterwards.
Think his account is somewhere between 10-20 minutes in this video 0. https://www.youtube.com/watch?time_continue=68&v=G6zFBzadTw0...
Chances are the people who got stuck selling at negative prices were actually doing just what you describe, they just weren't planning on the spread blowing out from physical issues.
And you typically should close out combination orders well before expiration.
Guys like myself, an ex fund manager, could be tourists in the oil market. I know I was, speculating occasionally on oil without knowing a whole lot about the details. Plenty of macro guys are similar, they bet on the large movements as the opportunites present themselves and don't worry about the details.
So what has probably happened is some of these tourists have had a few contracts left over that they forgot about or didn't discover in their position keeping until their prime brokers phoned them, and they had to dump into a market under very special conditions. Hopefully not very many contracts.
In normal times if you screwed up and had to do delivery, it stil wouldn't be a big problem, because the storage is available and you essentially just buy it (by trading with a guy who actually knows how to organize it), costing relatively little.