Many countries have already grounded 737 Max planes and as of Mar 13, 2019 the FAA have stated:
The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft (PDF) operated by U.S. airlines or in U.S. territory. The agency made this decision as a result of the data gathering process and new evidence collected at the site and analyzed today. This evidence, together with newly refined satellite data available to FAA this morning, led to this decision.
So why are there currently 40 737 Max planes in flight according to FlightAware?
Who would be liable should one of these flights crash on takeoff, potentially over a densely populated urban environment?