A shipped IA starts decaying the day the next team adds a page in the wrong place. Governance is the set of agreements that slow that decay: who may create a top-level label, what evidence is required to add a category, how redirects and aliases are handled when something is renamed, and how often the structure is reviewed against search logs and support tickets. Without those agreements, every release becomes a quiet renegotiation of the map.
Good governance is light enough that teams still ship, and strict enough that exceptions are visible. A practical pattern is a small IA review for changes that touch navigation, taxonomy, or cross-site templates, not for every content edit, plus a living style guide for labels and a changelog of structural decisions. Metrics matter here: rising "no results" queries, growing orphan pages, and support contacts about findability are governance signals, not only content bugs.
Strategy decides what the structure should be. Governance decides what happens the hundredth time someone wants to bend it.
Pause, name an owner, and review against known confusion. Shipping first treats navigation as disposable UI. A total freeze treats it as untouchable stone. Hiding the item from sitemaps and search creates a second, invisible IA. Governance that works here is a named decision path that can still say yes: just not silently.
A lightweight rule that often works: campaign destinations may be linked from content and banners freely, but new top-level labels require a short IA review and a sunset or merge plan dated in the changelog. Speed stays available; permanent map changes stay deliberate.