Should private LoRaWAN networks use a different sync word?

TTN Network and Services
2

This, obviously, isn’t correct. A officially assigned NetID isn’t required for a private network. But 0 and 1, typycally used for private networks, surely are NetIDs too.

https://lora-alliance.org/sites/default/files/2018-11/20181114_NetID_FAQ.pdf