We define sneaking as an attempt to hide, disguise, or delay the divulging of information that has relevance to the user. Sneaking often occurs in order to make the user perform an action they may object to if they had knowledge of it. Sneaking behaviors may include additional undisclosed costs or undesired effects from a particular action. Many of Brignull’s original dark patterns are of this type, and were the most common when dark patterns are referenced by practitioners.
Continues to charge the user after the service they have purchased expires. This pattern takes advantage of users’ failure to check up on service expiration dates, either for a free trial or for a limited-time use of a paid service, by assuming upon service expiration that the user either wants to continue the paid service or upgrade to the paid version of the free trial, and charges the user for either respective option and continues the service.
Provides users with a late disclosure of certain costs. In this pattern, a certain price is advertised for a good or service, only to later be changed due to the addition of taxes and fees, limited time conditions, or unusually high shipping costs.
Adds items not chosen by the user to the user’s online shopping cart, often claiming them to be a suggestion based on other purchased items. This may cause the user to unintentionally buy these items if they do not notice them prior to checkout.