Even the CIA flights of kidnapped people to the various black prison sites were public. Using that data, the Austrian Airfoce intercepted and escorted one of those flights out of Austrian airspace.
It doesn't matter if its publicly available. To aggregate the data in such an easily accessible form is an invitation to crackpots. Few crackpots are going to seek out such information unless they are truly dedicated from the get-go.
Before ElonJet was suspended their pinned tweet pointed out that Twitter's acceptable use policy was that it was ok to republish data generally available elsewhere - which is exactly what this is. It would be illegal to operate the jet and not publish its location.
So we are imagining someone is dedicated enough to go to jail for the rest of their lives for some assassination attempt but not quite dedicated enough to look up information themselves?