One in a thousand wouldn't yield anything. Because it's such an unusual experience (just a few of these happening around the same time would create a news cycle), one in ten million is probably closer since there are around a billion active Apple accounts.
That's similar to the odds of dying in a non-Boeing plane ride. Even if the odds were one in a million, that's about the odds of being struck by lightning over a lifetime.
I'd think someone returning a phone over this was regretting the switch for other reasons. It's fine to keep using Android.
This is a reasonable point of view I guess. But there's not really a reliable way for the consumer to get the real probability. If it happened to me, it's likely enough to consider. Maybe there's a hidden variable about my usage pattern that makes it more likely. Since it's totally opaque, there's no way to know.
Sure, if actually happens to someone, they're rightfully not risking it again. If for no other reason, it'd be likely that a fresh account would be detected and associated with the old one. Plus, whatever unusual situation of yours triggered the ban, such as border crossing or how you route your Internet traffic, would probably still apply. (I'm not saying someone is doing the wrong thing if those things are the case for them.)
Likelihood should affect your behavior in the same way it affects whether it actually happens and it did.
"Fool me once..."