A shopping cart is supposed to answer a simple question: what did I choose to buy?
That stops being simple when the checkout quietly answers a different question: what else can we get away with adding?
The Federal Trade Commission’s dark-pattern report uses the term sneak-into-basket for designs that automatically add an item without the shopper’s permission or use a pre-checked box to push an unwanted purchase into the order.
See the FTC’s Bringing Dark Patterns to Light.
The cart total changes before the customer’s intention does
The extra item may be insurance, a warranty, a membership, a donation, a delivery upgrade, a service fee presented as optional, or some other add-on.
The important part is not the category. It is the sequence.
The customer selects one product. The interface introduces something else. The shopper must notice the change and remove it rather than affirmatively choosing to add it.
That reverses the normal meaning of consent.
In a 2026 sweep of online sales practices, European consumer authorities specifically identified adding items without a consumer’s consent as a misleading practice. The same sweep found websites using fake scarcity claims and late-added fees, showing how basket manipulation often appears beside other pressure techniques.
See the European Commission’s 2026 online sales sweep.
A transparent checkout should survive a quick glance
A clean confirmation page should make three things obvious before payment:
What products are in the order. Which optional services were deliberately selected. What the final total is.
Anything newly introduced should require an affirmative choice rather than an opt-out hidden among the rest of the checkout.
The FTC’s current fee guidance makes the same distinction in pricing terms. A supposedly optional charge is not meaningfully optional if it is included by default and removed only when the customer notices and objects.
See the FTC’s Unfair or Deceptive Fees FAQ.
The problem is not that stores offer extras.
The problem begins when the checkout treats not noticing as the same thing as wanting.
A cart should record the customer’s decisions.
It should not manufacture new ones on the way to the Pay button.