BigQuery Can Reconstruct the AI Traffic GA4 Hides
GA4’s channel classification discards referrer data that BigQuery’s raw event export preserves. The collected_traffic_source record and page_referrer event parameter contain the original source information for every session — including AI-referred visits that GA4 dumped into Direct. A SQL query against the BigQuery export can surface AI traffic that the GA4 interface will never show. Loamly found 70.6% of AI sessions arrive without referrer headers, but BigQuery also enables behavioural pattern matching — landing page analysis, session timing, and engagement fingerprints — to probabilistically identify AI-driven visits even when the referrer is genuinely absent.