What happens to structure creation if I enable lifecycle validation?

When lifecycle validation rules are enabled, they ensure that only components in the same lifecycle phase or higher lifecycle phase than the parent item can be added.

The only exception is made for a deprecated lifecycle phase. Component items in this lifecycle phase can't be added to an effective structure. For example, the parent item has lifecycle phases of Concept, Design, Prototype, Production, and Obsolescence. It's currently in Prototype lifecycle phase. When adding a component to this item's structure, the component should have a cycle phase of Prototype (same as the parent item) or Production (higher life cycle than the parent item).