Contest policies

YouTube requires official rules for any contest you run. Those rules have to state that YouTube is not a sponsor, release YouTube from liability, and carry a privacy notice covering data you collect. You are responsible for administering everything lawfully and for awarding prizes exactly as your rules describe.

Local law is the larger risk. Requiring a purchase, and in some places requiring a subscription, can turn a giveaway into a regulated lottery, while eligibility, minimum age and prize declaration rules change from one country to the next. What catches creators is the boring end of it: unpublished rules, an illegal entry mechanic, or a prize that never arrived.