Looks like we're not making warnings very scary. Might be worthwhile to make them... a subtle yellow or orange so they stand out a tiny bit?

This is how it looks today (http://googlecloudplatform.github.io/gcloud-python/storage-blobs.html#gcloud.storage.blob.Blob.rename)