This thread seems to be over complicating things. Flying with your drone is no different than flying with a slr camera or a tablet. Batteries in your cabin luggage - that's all there is to it.
Best bet is by far to buy from FB Classifieds or CL, because you get to fly the drone, see first hand how it behaves, run a check on the serial # and bind it to your account.
When buying from the Classifieds forum make sure that the seller has...
It is not the DJI demosaicing algo. I have looked at 3s DNGs in Photoshop. The color fringing is ludicrous. And AI denoising if ineffective. There is something much weirder going on.
There was an example posted earlier in this thread. Here are...
Moire filters have not been in widespread use in still cameras for quite some time. I have never seen anything like the DJI "moire" on any other camera.
Next two batteries came with cycle counts of 0 and 1. I flew the first battery today, drone did not fall out of the sky, did not catch fire :D and flew for a normal duration