Publisher-declared location

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Location supplied by the publisher/app (e.g. a self-reported profile city or content geography) rather than device-observed, is far coarser and more gameable than GPS or IP-derived signals, but is often merged into the same location field without a source tag.

Detection

Bidstream/segment record has a location field with no accompanying source/method attribute distinguishing declared from observed.

Mitigation

Require and preserve a location-source enum (declared vs. observed vs. inferred) on every record
Weight or exclude declared-location records separately in geo-targeting logic

Affected conversions

Point → H3 exact