And as with most things, the burden is on you to the extent that you want to actually prove them wrong. If you don't find yourself going back to California and you're willing to get a nasty letter from them every now and then, it's really a non-issue even if they firmly believe you are/were a California resident. They can't lien property outside of the state. If they put something on your credit report, you can dispute it with the reporting agency (who are much more likely to be reasonable than some FTB bureaucrat). Yes it can be a pain in the ass but I don't think it's nearly as big of a hurdle as TFA is making it out to be.
The IRS also looks at if you have joined a church or other social organization in PR. That's a rough one for me if I get audited. While I didn't end up going to PR, I left the country two years ago and during an audit I would not fare well not being able to point to any social organizations, relationships with the opposite gender, or friendships I have overseas even though lawyers suggest setting all of these up. I'm not that social so I'm at risk and hope I don't face an audit. (Covid was a big factor in avoiding social contact too.)
Although all the about is IRS related, I think it's well established that states often work with the IRS procedures as inspiration for their own
That's quite out of scope of the California thread though, as it is a much more complex situation. Income in PR is not subject to US taxation (even federal) so it's quite unlike moving in or out of a state like California.
Substantial connection tests and such
[1] - https://en.wikipedia.org/wiki/Category:Banks_based_in_Califo...
Not really. There's no legitimate reason one would have to sell all property in a state when moving out, for example. I should be able to keep them as rental units as long as I legitimately live in some different state.
A friend had to even sell off some empty undeveloped land to fend off California taxes, even though there was no way he could be claimed to live there, it was just empty land!