Not a likely scenario, FWIW: https://www.military.com/history/5-reasons-why-geography-ame...

I would expect any invading forces would need to be surveilled by planes or satellites, or perhaps drones, since they would immediately destroy something like flock cameras.

You're assuming that the invaders can't just buy, hack, or social engineer, access to the cameras from Flock. Lately it has been social engineering: https://www.404media.co/floridas-wildlife-cops-are-searching... but there's also a concern that the cameras themselves have compromised supply chains and may serve other masters: https://www.404media.co/new-jersey-used-covid-relief-funds-t...