In the case of an emergency like this. I would think that most 60hz devices could work on 50hz, and most 50hz devices would work on 60hz.

things that would get screwed up are devices that use the signal to time events. some high voltage switches use these things, but overall, i bet washing machines, dish washers, computers, lights, tvs, and radios would just work.

even garage door openers should work.

clocks and larger equipment might be a bust and maybe some of the robotics stuff at plants might be a bit off, but maybe just maybe it would work. these things are designed to condition the power in most cases within a few percentage points anyways.

i bet if it's that dire, they give it a go.