Why APEC is different
A forum that already runs on an arrangement
APEC is an economic forum, and Taiwan participates under a name and status that differ from its participation in most other international bodies. That arrangement has been in place for decades and is a recurring source of negotiation before each summit.
The venue matters here. This summit is being held in China, which adds a layer to the usual arrangements. Assurance requests before a summit in that setting are standard practice, though the reporting suggests this round required more than usual.
We are not drawing conclusions about what Beijing agreed to. The reporting describes the request for assurances, not the response.