One of the studied showed that teams that completed the checklist had lower mortality, but argued that the teams completing checklists might be systematically different from the teams that didn't complete the checklists, and thus the difference could not be attributed to the checklist, per se. Not wrong, but doesn't amount to refutation.

Note that in the debate you cited both, proponent and opponent, advocated the (continued) use of checklists.

Side note: I could see how you could do a blinded RCT, but not how you could do a double blind RCT here.