Annex I contains a list of commercial practices which are to be considered unfair in all circumstances and which are therefore prohibited. The list was drawn up to enable enforcers, traders, marketing professionals and customers to identify such practices. It therefore contributes to enhancing legal certainty. As stated in Recital (17) of the Directive, these are the only commercial practices which can be deemed to be unfair without a case-by-case assessment against the provisions of Articles 5 to 9. In other words, if it can be proved that the trader has carried out the practice in actual fact, national enforcers do not need to apply the material distortion test (i.e. to consider the impact of the practice on the average consumer's economic behaviour) in order to act and inhibit / sanction the practice.