I am admittedly one of those going off Flightradar24 but only in the above described circumstances i.e. when I can see that the plane is en-route significantly late and I'm somewhat aware that, as hard as they'd try, the next flight is also going to leave with a delay. Concerning the automatic gates, a few weeks ago I got to the airport (Warsaw) roughly 1 hour after the originally scheduled time of departure for my flight to Rome and got through okay (needless to say, the incoming Alitalia flight from Fiumicino had a 2+ hours delay due to thunderstorms in Italy) whereas most recently, in Belgrade, I left the office pretty late and, due to traffic, I arrived at the airport literally 30 minutes before the flight (adding to misery, the incoming LOT flight from Warsaw had docked 20 minutes early) - again, no problems but there are no e-gates at Belgrade, someone would manually check your boarding pass before passports and security is located directly at the gate so that may have saved me somehow.

G