Plasma trust model explained is about how much trust user give to operator and how system reduce that risk. In Plasma, operator bundle transactions off chain and post root to main chain. Users dont blindly trust this, because there is fraud proof and challenge period to detect bad behavior. If operator cheat, anyone can submit proof and block get rejected. Users also can exit with funds if they feel unsafe. So it not fully trustless, but trust minimized with verification and incentives.
