Reject-all is the choice most banners get wrong. Honor it completely, load nothing optional, and make changing the choice easy.
Test the banner the way a visitor experiences it: fresh session, accept on one pass, reject on another, on every key template before the freeze.
Most stores should use a certified CMP: maintained Consent Mode wiring, correct TCF mapping, and regional rules out of the box. Build custom only with a real reason and a named maintainer.
Declines send cookieless pings, not nothing. GA4 models the gaps above data thresholds. Consenting traffic is unchanged, backend numbers stay ground truth, and the consent rate itself is the KPI controlling data quality.
Treat the diagnostics panel as a triage list. The common flags are a missing or late default state, updates that fire after tags ran, bad TCF mapping, and tag timing races.
Check the default consent state before any tag loads, walk the accept, decline, and preference paths, and confirm the stored choice survives the full journey.
Google's documentation calls for a default consent state before any tag fires. Here is what breaks when it is missing.
A drop is expected at first: when visitors decline cookies, Google can no longer observe their conversions directly. What matters is whether the.
Advanced Consent Mode produces more complete modeled data because tags load immediately and send cookieless pings before consent. Basic mode blocks.