They allowed him to keep the extra money as a gesture of 'goodwill'.
a 'goodwill' ambassador on a 'goodwill' tour/mission
She has/feels 'goodwill' toward all her coworkers.
(..) he's predictable, he's boring. Milton has gotten success, whatever that means, so now he's scared. He won't take any risks at all. He's squandering the goodwill of his audience with tired, - second-rate tricks... - They're all favorites. Give me something fresh. (..)2006 The Prestige