I haven't heard that but it sounds like a good idea.
High acid foods can eat through the lining of the can. It's called *detinning*, and once the lining is gone, the acid destroys the metal. I actually saw that happen to maple syrup once. After that, when I buy maple syrup, I heat it to boiling on the stove and put it in hot jars and put a hot lid on it and screw the band down tight.
There's no need to process it as the temperature of something that high in sugar is well above boiling.
“I’ve heard you can buy canned sauce and just transfer it to jars and reprocess it.”
For true SHTF long term storage spread it out and dry it then bag or jar it. It will also reduce the bulk by 90% or better. just re-hydrate when needed. :)