The same rules like for 'same household' applies to any LAN event:
If you play from the same household (example: husband and wife, father and son etc.) you must play the same realm. If you try to play different realms, it will be considered cross-realming.
1.2 A player is not allowed to log his/her account and another players account at the same time.
1st offense: Warning and 3-day ban for both accounts
2nd offense: Permaban for both accounts ( If the second logged account was not involved in the 1st offense, the account will receive the 3-day ban)
If you are playing from the same household and one of you has to AFK for more than 10 minutes, make sure to log out of the game as you might get tested for dual logging. If, after 10 minutes, the test fails, the ban will be applied.
https://playphoenix.online/rules