Comment by ineedasername

Not really done properly: They were testing out the integrity of the system. This includes the process by which they notified the maintainers not to go ahead. What if that step had failed and the maintainers missed that message?

Essentially, the researchers were not in control to stop the experiment if it deviated from expectations. They were relying on the exact system they were testing to trigger its halt.

We also don't know what details they gave the IRB. They may have passed through due to IRB's naivete on this: It had a high human component because it was humans making many decisions in this process. In particular, there was the potential to cause maintainers personal embarrassment or professional censure by letting through a bugged patch. If the researchers even considered this possibility, I doubt the IRB would have approved this experimental protocol if laid out in those terms.