It's the same question right now. This is the WN forum, so we're primarily talking about domestic flights. To my knowledge, except for a few scenarios like NY/NJ to FL, the government has not prohibited domestic flights. If WN chooses to cancel a flight that they are otherwise legally and operationally allowed to fly, then they are indeed "at fault" for that decision and must, in accordance with the DOT rules, offer a cash refund.