Customer wants a feature that would compromise data governance — push back

Acknowledge the underlying goal ("you want a unified view"). State the specific governance constraint (e.g., PHI, GDPR right-to-be-forgotten, FedRAMP boundary). Propose two compliant alternatives: (a) in-customer-VPC processing with only anonymized results leaving the boundary; (b) a federated identity model so the same view is achieved without moving data. Offer to scope a small POC of (a) in 2 weeks. Never pretend the legal answer is "we'll figure it out," and never over-promise a workaround.