They could just sidestep it, by making the electricity free but the transport or cable use more expensive, no?

That's what is happening, the daily supply charge has been bumped up as well as the $/kWh during the other periods.

But it will still have the desired effect of shifting usage patterns, especially for people with rooftop solar and/or batteries and/or EVs.

We have a very large penetration of rooftop solar (due to government subsidies) and now home batteries as well.

There's definitely been a shift in the market "after sunset" when the coal "baseload" and gas peakers used to make their money.

The batteries are flattening out those spikes dramatically.