I'm pretty sure that most countries have done this since around WWII. Not to say that surprise bombings don't happen.

However, especially when the goal is to displace civilians to move in your own people. Regardless of what the message on the flyer says, best to always it read it as:

*"Hey! We are going to bomb the fuck out of your home to demolish it for our new luxury condos" *

Bombing civilian centers are legitimate military targets, to fascists, because the population there all must be supporting the destruction of their own people just as much as the fascist are destroying others. "Factory workers are just as guilty as the soldiers, for building the soldier's gear" is the reactionary logic.