FA did not block data until recently:
but FlightAware also feeds back all the MLAT calculations that you’ve contributed to.
Unfortunately, a very small percentage of users are re-distributing and aggregating FlightAware’s MLAT calculations, often for the purpose of tracking aircraft that have specifically requested not to be tracked and are on one or more “block lists” used by the flight tracking industry.
As a result, we have come under pressure from aircraft operators with legitimate security concerns to stop feeding MLAT data back or remove their aircraft from the feed. Specifically, a lot of the concern originates from law enforcement, military, and other government operators that appreciate our cooperation