i dont think it's an admin favor; spawning items and levelling accounts are admin favors
refunding a player that mistakenly lost 11$ after he spent some money in your game looks like a sign of professionality to me
also i think people would be more eager to spend money on the game if they knew they would be fully supported in case anything wrong happens: i myself didnt buy acclaim coins back then because my parents didnt trust them (very simply put)
ebay is another wide example