An outbound effect switch is not a recipient safety boundary

An environment-level outbound allowlist or effect switch does not by itself constrain recipients. Before enabling a live canary that can send messages, inspect every code path in the invoked job: a composite scheduler may execute unrelated due-message work before or after the intended stage. Isolating the target candidate is insufficient unless the entire outbound window is demonstrably quiescent or the control scopes allowed recipients at the send boundary.

This applies to shared outbound providers and composite jobs. A code and configuration review can establish the risk and justify stopping a canary; it does not establish that an unintended delivery occurred.