Stepping through this, the average year for colony establishment is 1678, which is 340 years ago. Two qualifying events in 340 years is a 0.5882% annual chance of nationwide violent revolution against the ruling government. Do the same math as we did above with the floodplains, in precisely the same way, and we see a 37% chance that any American of average life expectancy will experience at least one nationwide violent revolution.
This is a bigger chance than your floodplain-bound home getting flooded out during your mortgage.Buy more ammo. And another gun, if you can.