The area is already cleared well before. as soon as all doors are closed its usually clear already. The pushback truck is also connected well before the aircraft is even ready for push and start. Usually you’ll get “pre-departure check performed, all doors and hatches closed” before you ask for start-up, meaning the areas is clear.
Besides, the beacons won’t help clearing the area, if someone is walking below the aircraft to remove some chocks, he won’t be stopped by a beacon anyway as he knows you won’t get the all clear signal before he is gone (if he even notices the beacon lights at all).
The beacon lights are completely separate from aircraft movement or pushback. At some airports or certain stands its not allowed to start-up at the gate or during push-back, in case of APU failure you might need a ground air source and GPU to start at the gate. If you for example perform engine start-up after pushback, you will switch the beacons on after push-back, it has nothing to do with the push-back.
I know you can’t fully simulate everything in MSFS but thats how it is in real life. Closest to the real thing would be:
- Imaginary “departure check performed, doors hatches closed” from ground crew
- Request start-up
- Imaginary start-up clearance received → beacons on.
- Complete before start checklist (below the line).
- Engine start.
Its a little bit more fluid in real life, if it does happen that ground crew isn’t ready you could perform everything but just hold at beacon light on the checklist and wait with requesting start-up and beacons until ground staff is ready. Under no circumstance do you use the beacons to signal people to get out of the way. If the area isn’t clear, you are not ready for start-up and since start-up clearance is only valid for one minute you should not have requested start-up yet.