# Lesson 3 complete: deal-breakers and patterns

Learner finished lesson 3 with all quiz answers correct. Treat as known: reject BC-only locks/leader election, cross-origin bus, BC-as-database, bulk transfer fantasies; green-light logout / theme / invalidate with small signals + local/durable truth; no history replay; Safari 15.4+ baseline with optional storage-event fallback; two-tab hands-on checklist. Next ZPD: synthesis decision playbook (mission payoff) — full briefs through job → wire → truth → ship gates.