Sales negotiation
A SaaS vendor sets up automatic renewal and pre-ticks the premium option by default. Most customers, out of inertia, change nothing: renewal and the higher tier become the path that requires no active decision.
Make the desired offer the default option (renewal, recommended plan pre-selected); keep change possible but slightly more effortful.
Maximises retention and average basket without argument; inertia works for you.
Defaults deemed abusive expose you to sanction (consumer law) and to distrust.