It seems maybe a bit overconfident to assess that one instance doesn't know what other instances are doing when everything is processed in batch calculations.

It seems maybe a bit overconfident to assess that one instance doesn't know what other instances are doing when everything is processed in batch calculations. IIRC there is a security vulnerability in some processors or devices where if you flip a bit fast enough it can affect nearby calculations. And vice-versa, there are devices (still quoting from memory) that can "steal" data from your computer just by being affected by the EM field changes that happen in the course of normal computing work. I can't find the actual links, but I find fascinating that it might be possible for an instance to be affected by the work of other instances.