Amazon SageMaker Is Responsible for My Surprise Bill

> My IAM user session times out after an hour. This is annoying, but I’ve learned to live with it. Why does a Canvas “session” not time out apparently ever?

Who knows? I've found that Cloud9 has a timeout value, but if you set the timeout to a value that isn't in the dropdown in the UI (like if you're deploying with CloudFormation or the CLI) then it just never shuts down.