What is the difference between me subscribing to BBC and watching it in Oz, or me subscribing to SBS and watching it here?
As far as I can tell, you cannot subscribe to SBS at present (you could before 2015 for some years, to some of their channels). If you subscribe to the BBC, you're actually subscribing to something like BBC UKTV which is a commercial service with different channels.
And yes, some VPNs specifically mention watching geo restricted material as a benefit.
Which ones? I don't think anybody has yet posted any example of a service that says it's fine to do this unless you're a subscriber and the material is georestricted to your residence. I suspect you're seeing what you want to see and ignoring their warnings (which they often put lower down the page and/or in smaller size, because it's not in their interests to dispel someone's prejudice on this before they've got their money).
I quoted the warning from Proton earlier. Surfshark say to use their VPN to avoid your ISP throttling your connection when they notice you're streaming, and to access local content while abroad, and has a big "disclaimer" warning you that "using Surfshark services for any illegal activities is strictly forbidden and violates our Terms". Nord VPN say they're for "safer and smoother access to your social media, games, and legal streaming platforms that you pay for" and nothing about getting access to streams that aren't normally available to you. ExpressVPN is probably the biggest provider that gets closest to saying they're happy to take payments from users who are ripping off TV from other countries, but even they still include "you are responsible for complying with our Terms of Service, your content provider’s terms, and any applicable laws" on their streaming page and on another page they say "If they detect VPN use, they may block access or restrict content availability. While a VPN helps secure your connection and protect your privacy, it does not guarantee access to region-specific streaming libraries."
Some of their paid advertisers say VPNs can be used to break georestriction, but that's not the same thing as the VPN provider saying it, just like safety kit makers aren't punished when their retailers go too far with unsubstantiated claims about how protective the kit is.
I don’t expect them to defend me but they aren’t going to go out of their way to block me either.
Handling abuse reports by disconnecting troublesome users isn't "going out of their way". It's a core business function of an internet service, else they're in big trouble when a vandal buys an account and starts using it to deface websites, as they get blocked by loads of other businesses and eventually cease to have a service that they can sell. Tracing and then noting, warning or booting a user who's broken the terms is usually a pretty slick operation once they put in the exit IP address and time from the complaint. (I used to work for ISPs, and knew some who worked in a big ISP abuse / fraud department.)
And just to repeat again: unless you take the pee, the worst that's likely is to be blocked off the streaming service you snuck into. But if too many start doing this, it's pretty easy for the VPN accounts to be toasted too, especially if TNT, FLCS, ASO, RCS or whoever starts applying pressure to broadcasters to get tougher. We saw that happen with football when it went behind the paywall, we saw that happen with F1, we even saw that happen with golf. We may thing it's wrong and stupid, but it's hardly unforseeable. In theory, your internet connection is at risk too, but that's much less easy for them to get behind a VPN, as far as we've seen so far. You place your bets and takes your chances. Just please don't mislead people about how much they would be betting if they follow your example.