The good folks at the Office of Film and Literature Classification Office tell us they've updated their plain English guide to the censorship laws to reflect the recent legislative changes.
I find anecdotes can be helpful.
Suppose that your 17 year old brings some friends over to watch Game of Thrones. They're all aged 16-18.
If they're watching it on Sky, it's ok. The broadcast comes after the watershed and comes under the Pay TV code of the Broadcast Standards Authority. The warnings are advisory and do not carry legal penalties for viewers.
If instead they're watching it on DVDs you'd purchased, you are in breach of Section 125, which makes it an offence to supply, distribute, exhibit or display a publication contrary to its classification or to allow another person to do this. The fine is up to $3000.
But, now that you know that Game of Thrones Season 4 Episodes 7 & 8 are considered R18, you've supplied it with knowledge that it's age restricted. And so it's Section 126, which has imprisonment for up to 3 months or a fine up to $10,000.
If they'd watched it on Netflix or Neon, you'd be in the same trouble as you'd be in if they'd watched it on DVD.
This kind of plain English explanation can be particularly helpful in explaining precisely how wonderful our current regime is. We can't blame the Censor's Office for this - the legislation is idiotic and needs an overhaul.
But we can wonder about whether it's reasonable to set a rating that makes it illegal to watch a show on DVD that is legal to watch on broadcast. The Censor's Office has RP13 and RP16 ratings it can use allowing children to view the material only when with a parent or guardian. Is it really sensible to set anything that can air on Sky TV as having a harsher rating than RP16?