Bambu Studio also has the hardcoded private key present to talk with the printers
Probably starting with Bambu Studio 1.10.2 Public Beta. Before that, no such keys were needed in LAN mode (as it should be). Also, the keys will expire from time to time, requiring users to go online again. And who guarantees that keys will still be released for today’s printers 10 or 20 years down the road?