Reviewing who can see each memory before a page opens up
When you widen a page's privacy, you see the memories first and choose which stay for members only.
When you switch on Anyone with the link can read it, or make a page public, Beyond My Time doesn't just flip the switch. It shows you every memory that's about to become visible to more people, and lets you keep any of them for the people on the page only before the change takes effect.
You can run the same review at any time from Settings → Privacy → Review.
After a handover
When a page is handed to the person it's about, they see the same review when they arrive — it's their page now, and they should know what the world can see of it.