The kill switch is not the rollout flag
The rollout flag from launch was left at 100 percent and forgotten, and nobody on call knew flipping it was an option. Make the kill switch its own flag, named after the feature and listed in the runbook, with one sentence beside it saying what the customer sees when it's off.
summaries.enabled off → the summary box does not renderA switch is only useful if whoever holds it knows what happens when they use it.
reliabilityfeature-flags
Longer version: the post this came from.