As I understood it it's not against damage but so that they wouldn't get lifted from the roof and become projectiles. Since they're probably light compared to t

As I understood it it's not against damage but so that they wouldn't get lifted from the roof and become projectiles. Since they're probably light compared to their surface area, I can imagine that they'd fly around at least as easily as shingles. But maybe they can be attached well enough to prevent this.