I buy this, and I don't fear the expirement.

However, can we be sure that the cosmic ray example provides proof of safety? Will our expirement so directly mimic this that it guarantees similar results? Or will differences and/or imperfections in our version of the expirement create differences and/or imperfections in the results that can be disasterous?

I reiterate that I agree with the non-alarmist view here, just stating that differences in expirements that aren't accounted for, can often have traumatic results.