Solved

More than one account

Is it legal to have more than one account? In my league https://igpmanager.com/app/p=league&id=5217 there's a guy who joined with 4 accounts. (adrian nianco, agus bianco, johan sebastian, matias blanco)
Different names but he didn't think too much in their team names, all BAF something.

Yes, there are no consequences for having more than one account.

Some players try to use the game to their advantage by utilizing multiple accounts to test various styles of management.

In my opinion, having too many accounts can be a time suck and if a player's accounts are all in one league or one tier, it can certainly be frustrating for other players to compete depending on their strategy for each account in a race.

In my instance, I have two accounts in one tier, but I don't let my B-team try to interfere with the race or directly or indirectly assist my A-team win. My B-team is solely a filler account for the grid until my league can get more folks in the tier. My B-team's goal is to be as independent as possible from my A-team.