Implied consent
Implied consent is consent inferred from a person's behavior, such as continuing to browse after seeing a cookie notice, rather than from an explicit act, and it is not valid for non-essential cookies in the EU or the UK.Early cookie banners in Europe often said "by continuing to use this site, you agree to our use of cookies". That model ended with the GDPR, whose Article 4(11) requires a statement or a clear affirmative action and whose Recital 32 rules out silence, pre-ticked boxes and inactivity. The Court of Justice confirmed in Planet49 (C-673/17, 1 October 2019) that a pre-ticked checkbox does not give valid cookie consent, and the EDPB's Guidelines 05/2020 say that scrolling or swiping through a page does not meet the standard either. The ICO applies the same reading under PECR in the UK.
California has a parallel rule for the few cases where its law asks for consent: Cal. Civ. Code 1798.140(h) says that hovering over, muting, pausing or closing a piece of content does not constitute consent, nor does agreement obtained through dark patterns.
Implied consent survives in other legal systems. Canada's PIPEDA allows it in some circumstances, depending on the sensitivity of the information and the person's reasonable expectations, while expecting express consent for sensitive data. For a European audience, though, the practical answer is simple: a banner that closes on scroll or treats a dismissed notice as acceptance collects no consent, and the trackers it lets through run without a legal basis. See explicit consent for the stricter end of the scale.