I wouldn't trust that script too much: there is no error checking at all. What happens when s3cmd fails and after two months you discover the "Vault sync succeded" emails you have been getting were all illusory? If the author is reading: please take the time to update your example, including proper error checking (at least "set -eu"), otherwise the people on the internet that are going to copy your script are in for…
I will add what you proposed.
Thanks for your input.