At many international airports, once a passenger enters the "sterile" transit or departure area (airside), they are physically separated from the arrivals flow. In some airports, it is simple to walk back toward immigration/baggage claim, but in others, the architecture creates a "one-way" system where exiting requires a security escort or airline intervention.

How can I determine if an airport allows passengers to exit the transit/departure area after entering?
Details:

This is particularly relevant for long layovers where a passenger might enter a transit lounge for a few hours but later decide they have enough time to visit the city.

Aside from searching for specific "trip reports" for every individual airport, what are the reliable indicators or research methods to determine an airport's "exitable" status ahead of time?

E.g.:

• Terminal Design Terminology: Are there specific architectural terms (e.g., "separated flows," "sterile transit hubs") that indicate a one-way path?
• Map Cues: On official airport maps, what visual cues or labels (e.g., "no-return doors," "exit lane breach control") should one look for that suggest a path from the gates back to landside is restricted?
• Regional Standards: Are there specific regions or aviation authorities that mandate a physical separation between departing/transiting passengers and the arrivals hall?
• Official Guides: Do airport websites typically list this under a specific heading (e.g., "Transfer Information" vs. "Arrivals")?

I am looking for a way to identify this "point of no return", ideally during the planning phase (ideally, before my trip), so I can decide whether to go through immigration immediately upon arrival or head to a transit/airside lounge first.