Is one who repeatedly advertises an interest-based loan, playfully and forgetfully, then regrets his action, sinful?

Promoting what is forbidden, such as usurious loans and the like, is prohibited, and "the one who points to evil is like its doer." However, whoever issues such a promotion while forgetting its content will not be held accountable, due to the Almighty's saying: "Our Lord, do not impose blame upon us if we should forget or err," and due to the Prophet's (peace be upon him) saying: "Verily, Allah has pardoned for my nation their mistakes, their forgetfulness, and what they are coerced into." What is meant by this is the removal of sins.