The guardrails i.e. the classifier would also fire on Fable's output and even Fable's internals (i.e. prior to the shutdown people would see it firing when Fable got angry)
I believe you can be notified when a collection is imminent. I saw a service use that to remove instances from the load balancer before that happened - super useful for higher-percentile latencies.
https://x.com/repligate/status/2069150509978489287