To go easy on another player at the table (e.g., not betting or raising against him). Suppose you and your brother are the last two people left in a hand. On the river, you have the nuts, but he bets. If you don't raise, you are "soft-playing" him.
I guess this happens a lot.
I should look for it more while I play.
But if it does happen all you can do about it is Pull in the Table Mods and hope they look into it.
My question is why do people have to cheat to win.
Just put some effort in and learn how to play.
Soft Play and any other cheating methods.