The Australians started the trend of not making teams follow on after the famous Test in India (2001 ?). But I agree that teams may need to look at this again as things change.
Indeed. There's been plenty of talk over the past couple of days about how it's not the modern way to enforce the follow on, and there was little surprise that they didn't.
As much as it would be great to see Smith come unstuck if it backfires, anything that comes his way is done with a massive helping of hindsight.