That's not how that works. Your breakers are sized to support your panel size. If you have 10kW panels that can push 10kW onto the grid when the grid is live, they can push 10kW when the grid is down. The limiting factor is the power your panels produce which in this case is also...10kW.

You're probably right about linemen but there are a lot of other reasons not to feed power onto a dead grid.