I think just verifying references exist should be a journal-level task, like copyediting, or fact-checking at a magazine. It's not expert qualitative evaluation, you don't need eminent peers to spend time on it. It's something a junior editor or administrative assistant should do, prepublication. 1/

Journals I think want to claim they add value beyond the work they extract from peer reviewers for free. If they publish nonexistent citations, I think it's hard to take those claims very seriously. 2/

(You would think domain experts would be curious abt relevant work they'd not encountered, though! So it might not speak so well of reviewers either, if fake cites get through, even tho reviewers should not be expected to methodically vet all references. But not all cites are broadly relevant.) /fin