1. When the link is madeExposure: can the person making it see the asset, or every member of the collection? Otherwise 403.
2. Every time it is openedSignature, expiry and revocation, then lifecycle: an expired, scheduled or revoked asset stops serving (410).
3. The person gets the filea file, a listing page or a zip

• A hold never blocks a linkIt only keeps an asset available, so a held asset keeps serving.
• Collections drop members, not linksAn expired member leaves the page and the zip; the page says how many, never which.