We have never had a situation where the Reserve Bank Guarantee...

We have never had a situation where the Reserve Bank Guarantee has been called on that I am aware so who knows what would happen.

I doubt Australian banks would suffer a liquidity crisis unless there was a significant world wide recession - in Australia it would probably be precipitated by a massive default in residential mortgages.

The last event you could describe as a mini banking crisis in Australia was in the 90s when a number of financial institutions failed around Australia, including the State Bank of Victoria, the State Bank of South Australia, the Teachers Credit Union of Western Australia, the Pyramid Building Society as well as several merchant banks, a mortgage trust, and a friendly society. The BNZ in NZ problems / bailout shows what can happen when a large bank has issues.

Would the reserve bank default on the deposit guarantee probably not remember they create liquidity by "printing" money - the bigger question is what would money be worth in an economic meltdown such that say all the banks called on the guarantee and the Reserve Bank printed money. There have been examples over the years such as Germany after WW1 and in South America in most recent times of what happens when Governments just print money - I have no idea if the Reserve Bank would go down that path but I doubt it. In a really serious scenario the Govt might nationalise any banks in trouble.

While there might be a recession coming up I doubt we are going to go into a situation where Australian banks will be defaulting on their deposits.

if you are looking at coverage by the guarantee then my understanding is splitting your deposits with different banks is the way to go.

If you are concerned about protecting the value of your cash and are not sure of the best way you really need to talk to a number of financial advisors - tell them what your concerns are in terms of your investments, assess what they recommend and go from there.