Requirements about surcharge notifications and displaying all-up prices are nice, but the gap here will still be about enforcement and not regulation. The core problem for dollar-store shoppers in the US is about getting the retailers to honor the sticker price, not whether the sticker price shows all state and local taxes.

Is the Australian shopper protected simply by a stronger culture of adherence amongst retailers or is it because regulators inspect more often and take stronger action against failures?

Regulators take tip offs and if one gets through, the enforcement action is usually pretty fast and strong.

They also like doing this. The ACCC makes a huge deal out of parading their latest conquest in the media.

Has its faults, the ACCCs dealings with telcos are especially terrible.

I still have friends at an Applecare provider based in oz, and they had a big one where as a settlement with the ACCC over trying to have it both ways with consumer law, they agreed to provide repairs or replacements for like a decade of wrongfully denied hardware issues. Hushed it right up. It was in lieu of a public apology from memory. But my friends spent weeks calling back old customers, chasing new contact details etc, to try and get them all free replacements.

I guess it might be a cultural thing? The shelf price is the binding price here in practice. If you get to the register at the supermarket and the price is higher, you can just let them know and they will send someone to check the price and match it.

Yes, probably difficult to compare regulation and inspection.

As for enforcement, ACCC recently took Microsoft to Federal Court for hiding Copilot pricing shenanigans, as discussed: https://news.ycombinator.com/item?id=45721682