Earlier quoted context omitted.
Open weight models are much more auditable than closed models, but could still hide backdoors that could be near impossible to detect.
Correct. We need open weights, open code and open data. If nobody else can reproduce what someone did there will always be security questions. Even if we can reproduce it there could still be security concerns but it's more realistic to investigate yourself.
Even with this, the cost of verification would be enormous. You would need a massive cluster to repeat the training E2E.