i think they should be banned, because Transfer/Loan between same owner teams definitely not fair to other teams.
if same IP multiple teams but without any Transfer/Loan between them, then we still can consider different users with same IP, but now there got Transfer/Loan between these teams, this definitely consider as cheating.
if Premium account can own multiple teams, i think should set some rules to make it fair to other users with single team.
1. cannot be same nation
2. cannot Transfer/Loan between these multiple teams
i think admin must concern on it, because it is really really really UNFAIR to all of us with single team!
forgot to add 1 more rule
rule 3. all multiple teams must under same manager page, so we can know that that manager having multiple teams.
and all players Transfer/Loan are invisible for multiple teams under same manager, so they no chances to Transfer/Loan between them.
and if Transfer/Loan players under same IP but difference managers then consider cheating, must ban it!