I think Parrot would be one step ahead and probably embed the blacklist in the firmware on the drone itself, and as we know, nobody has managed to crack their encrypted system to interrogate the system/firmware.
As you say, you can ensure it never connects to the internet, but personally, I would avoid, to many "If's and but's"
And ultimately, what are you going to do in the situation where you cannot hack the blacklist? you are left with a drone you cannot fly or do anything with, you could probably part of some elements of it, but camera/gimbal and motherboard are married with embedded code, along with the blacklist possibly.
If its that much of a bargain, and you can spare the cash, take a punt.