Borrowing, in a way, looks a bit like the anchored pointers suggested by Henry Baker in [1]. I recall reading someone did a static analysis to detect what pointers could be anchored, but forgot which someone. However the "deferral" suggested is very different to the Deutsch-Bobrow deferral; what makes me think it is more like borrowing is that anchoring avoids destruction due to linear types, like borrowing avoids moving or copying. (Regions in Cyclone would be somewhere in between, too.)

[1] https://plover.com/~mjd/misc/hbaker-archive/LRefCounts.html