Glossary
Opt-Out Default
An opt-out default enrolls a principal in some ongoing behavior automatically, and requires them to take explicit action to leave it rather than to join it. This is a deliberate choice about where the friction sits: opt-out designs bet that most people, left to inertia, will simply stay enrolled, which is exactly why the choice of default carries so much practical weight regardless of how easy the opt-out mechanism technically is.
The same underlying question — which state does inertia favor — applies to authorization defaults generally, not just consent-flavored ones: a newly added feature that's on for everyone until someone opts out behaves very differently, in aggregate, than one that's off until someone opts in, even when both are technically reversible with equal ease.