fly on the wall
you have but-face.
They were still young and innocent.
They also had no idea about what was going to hit them.
I'm sure if they really knew what was going down, they would have stayed home.
I'm pretty sure Buffy didn't sugarcoat anything. Morally, I don't think she'd do that.
Notice how when the big snake appeared, no one ran? Screamed? Hid? They all rose up to the challenge. They had to know there would be deaths, but had they stayed home, and Buffy failed to eliminate the Mayor, they ALL would have died.