Absolutely, but just as it's not ok to enter someone's home just because they forgot to lock the door, it's not ok to exploit access at your old employer because their offboarding process missed something.
I do the same as GP does; I don't want there to be any chance that my former employer has forgotten to revoke access to something, so I make sure to clear out anything that might remain on any device that I don't return to them.
Who knows, maybe another former employee will decide to steal from them around the same time I leave, and me having access credentials on a personal device, even if I haven't used it, might arouse suspicion.
You get trustworthy people by trusting people. Generally when I was there there was a presumption of trust. Given how blatantly the defendants are alleged to have acted, that’s still the case.
> Generally when I was there there was a presumption of trust.
The reality is, there has to be. And, if you can't trust someone then don't work with them.
I was talking to an amazing lawyer/business person I know one day and I asked about writing 'air tight' contracts which would never put you in a position to be screwed. He said something along the lines of, that's impossible. Someone could take you to court and you could still lose even if you think the contract is perfect. What he said next stuck with me over the rest of my career, 'if you truly can't trust someone, no contract will be fool-proof. The solution is simply to not work with or do business with them.'
I do the same as GP does; I don't want there to be any chance that my former employer has forgotten to revoke access to something, so I make sure to clear out anything that might remain on any device that I don't return to them.
Who knows, maybe another former employee will decide to steal from them around the same time I leave, and me having access credentials on a personal device, even if I haven't used it, might arouse suspicion.