Tier 3 is the only architecture that generates verifiable compliance evidence as a byproduct

The verification regime emerging in 2026 (C-0003) requires an institution to demonstrate four properties on inspection: that data described in a plan exists, that it resides at the location the plan specified, that it has not been altered since deposit, and that access controls match the plan's stated terms. Each architecture produces evidence for these questions in qualitatively different forms.

Tier 0: Existence is asserted by the researcher; location is a personal device; integrity is implicit; access control is the device's owner. None of the four is independently inspectable.

Tier 1: Existence is checked by manual query to a repository portal; location is a claim from the provider that the customer cannot independently verify; integrity is an assertion about backups the customer cannot inspect; access control is a screenshot. Each opens a separate audit burden.

Tier 2: The consortium asserts the protocol is operating as documented. MetaArchive's 2025 sunset audit (S-0096) shows those assertions can silently fail with no external party positioned to catch it. When the consortium dissolves, the verification dissolves with it.

Tier 3: Content addressing makes integrity mathematically verifiable (RFC 6920, S-0010): altering one byte alters the hash. Distribution makes copy count and locations observable by inspection. A single cryptographic query across the distribution network produces evidence any third party can independently re-verify. The hash confirms integrity; the node list confirms location and copy count; the access layer confirms permission state.

The verification is not bolted on. It is a structural product of how the protocol operates. The institution can produce a signed attestation that the auditor can independently re-verify without trusting the institution. This is the property M-0002's three architectural principles produce when present jointly.