This seems to address concerns raised in another thread:
6 Giant Blind Spots In Every Movie Alien's Invasion Strategy | Cracked.com
Excerpt:
Everyone makes fun of Signs because it depicts an alien invasion that is thwarted because the aliens die if they touch water. But that's not the issue. It's not their fault that water is like acid to them, but it is their fault that they showed up naked. You have intergalactic starships, but you don't have goddamned pants? How does a civilization's evolution just skip over that part?
6 Giant Blind Spots In Every Movie Alien's Invasion Strategy | Cracked.com
Excerpt:
Everyone makes fun of Signs because it depicts an alien invasion that is thwarted because the aliens die if they touch water. But that's not the issue. It's not their fault that water is like acid to them, but it is their fault that they showed up naked. You have intergalactic starships, but you don't have goddamned pants? How does a civilization's evolution just skip over that part?