Major European airlines canceled many flights to Asia due to the coronavirus outbreak. Lufthansa announced that up to 25% of short-haul and medium-haul flights could be canceled as well. I was supposed to flight tonight with Lufthansa from BSL (France/Switzerland) to KRK (Poland) with a connection in MUC, but my flight to Munich was canceled. I've been rebooked for a flight tomorrow with a connection in FRA.
Since I'm going to have over 12 hours of delay, I'd expect to be entitled to compensation under EU261 regulation. It's almost certain that cancellations of intra-EU flights are done due to decreased demand. This cancellation can't prevent virus spread since LH didn't cancel other flights from/to this airport and I'm going to travel on almost the same route anyway, only with a major delay.
However, given the current situation in Europe, I'm afraid that the airline might hide behind extraordinary circumstances. After all, the airlines are never happy to lose money and they tried to use this exception incorrectly many times in the past. Is there a good way how I could prepare myself for filing the request for compensation after my travel tomorrow? Is there any better way to inquire about the reasons of flight cancellation rather than just calling the airline? Are they even required to tell me the reason?