When a user rates, they have the option to have their name revealed by explicitly using the Custom button or keep it hidden by using the Green button.
Those who want their name hidden use the Green button. Those who want to reveal their name use the Custom button. It is a choice made by the rater, and yes, many who explicitly want their names revealed use the Custom button.
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If you want your name revealed, you may use the Custom button. It is your personal choice.