Developers should be able to tag parts of the speech output response from their skill to be different depending on whether the user has reviewed the skill or not.
Thus I could request a review for my skill, tag that as only for users who have NOT already reviewed my skill, when skill responds Amazon determine whether user has already reviewed or not and only includes tagged element of message if they have not already reviewed. Likewise I could tag another element to play only to customers who HAVE reviewed the skill.
Main benefit from a customer perspective is that they don’t get asked to review a skill they have already reviewed. Also anonymity maintained as Amazon determine if customer has reviewed or not - not the developer.