My son and I have different accounts in FAF and often use the same PC to play. Sometimes we play together. How can we avoid banning for smurfing?

@axel12 TY for reply! Some time ago my son's account was banned for smurfing but it wasnt a smurf. He created a new one buying a new copy of the SC:FA in Steam. I just dont want his new account to be banned too. I can honestly name both accounts and don't intend to hide them.

My son and I have different accounts in FAF and often use the same PC to play. Sometimes we play together. How can we avoid banning for smurfing?