Interesting, I actually have a cash limit listed on my statement, but have no idea what my PIN is. Not that I'd use it for cash anyway. But having recently used it in Samoa actually I got chip errors and had to swipe and sign all the time, which is fine, just a bit 2005 haha. Obviously just never noticed in Australia, because I tap or insert and it just approves (or use Apple Pay), and online you don't use a PIN of course.
And yes fair point re the locks, maybe I'll get it eventually and have just been lucky so far. I guess with the absence of chip and PIN they have to be a bit more trigger happy. I thought I had been after my rental car company in Fiji (the same day as paying my hotel bill in Samoa) kept declining, but I've used it again since with no intervention, it was just that one transaction strangely (ironically I got a speeding fine, which the rental company charged to the Amex just fine
).