Just "company.com/pagerduty-service" as a "required" annotation (i.e. if you forget your namespace's team gets a reminder at their E-mail, which is another required annotation)

Namespace onboarding is self-service by pull request: a template namespace is in the readme, and contains a number of standard annotations like ldap group and etc. The kubernetes admin team accepts and merges those requests and the bot deploys the namespace folder to the clusters.

This is basically zero overhead at small groups and scales well to giant companies, you just add annotations and sometimes labels as business requirements and structure dictate.