On any checkout, sign-up, or consent screen, read each checkbox and toggle before you continue, noting whether it is already ticked and whether ticking means yes or no, because defaults and confusing wording are how extras, marketing consent, and data sharing are obtained from people who never chose them.

How to do it

1. 1Slow down at the last screen before payment or "continue". That is where the additions are placed, because attention is lowest when the goal is in sight.
2. 2For each box, establish its state and its meaning: is it pre-ticked, and does a tick mean opt in or opt out? Watch for double negatives ("untick if you do not wish not to receive") and for adjacent boxes that alternate between the two.
3. 3Untick anything that adds cost: insurance, extended warranty, priority handling, donations, "protection" plans, trial memberships.
4. 4On consent banners, look for "reject all" or "manage options". Where only "accept all" is prominent, open the settings and check that the toggles, including those under "legitimate interest", are off before saving.
5. 5Review the order summary line by line against what you meant to buy, and check the total against the advertised price.
6. 6Take a screenshot of the final screen for anything expensive. It is your evidence if an unrequested extra appears on the bill.

When to use it

• •Booking flights, hotels, car hire, and event tickets.
• •Installing software and creating accounts.
• •Cookie and privacy consent banners.
• •Signing electronic forms for finance, insurance, utilities, or phone contracts.

Counters

Evidence and how strong it is

Default effects are among the most robust findings in behavioural science. Johnson, Bellman & Lohse (2002) showed that whether a consent box was pre-ticked, and whether the question was phrased as opt-in or opt-out, roughly doubled the share of people who ended up agreeing to be contacted. Johnson & Goldstein (2003) found that countries with presumed-consent defaults for organ donation had far higher registered consent rates than opt-in countries. Luguri & Strahilevitz (2021) tested dark patterns on a representative US sample and found that mild ones, including pre-selected options and trick wording, more than doubled acceptance of a dubious paid service, and aggressive ones nearly quadrupled it. The law has responded: the EU Consumer Rights Directive forbids pre-ticked boxes for additional payments, and the EU Court of Justice held in Planet49 (2019) that a pre-ticked box is not valid consent. Evidence strength: strong (repeated experiments and field data) that defaults and wording steer choices; the defence, which is attention at the point of choice, is logical but has not been separately trialled, and attention is exactly what these designs are built to exhaust.

1. Johnson, E. J., Bellman, S., & Lohse, G. L. (2002). Defaults, Framing and Privacy: Why Opting In-Opting Out. Marketing Letters, 13(1), 5-15
   Experiment showing that pre-ticked boxes and opt-out phrasing sharply increase the share of people who consent.
2. Johnson, E. J., & Goldstein, D. (2003). Do Defaults Save Lives?. Science, 302(5649), 1338-1339
   Cross-country and experimental evidence for the power of defaults.
3. Luguri, J., & Strahilevitz, L. J. (2021). Shining a Light on Dark Patterns. Journal of Legal Analysis, 13(1), 43-109
   Experiments on a representative sample showing that mild and aggressive dark patterns multiply acceptance of an unwanted service.
4. Court of Justice of the European Union (2019). Bundesverband der Verbraucherzentralen v Planet49 GmbH. Case C-673/17, judgment of 1 October 2019
   Ruling that a pre-ticked checkbox does not constitute valid consent.