Signs

A tip: don't think up a topic for a blog entry and then put it on your mind's rear burner for years. The Crooked Timber commenters will get there before you do.

Anyway, what I was going to say was: the ending of the movie Signs makes no sense. If water is toxic to the aliens, then they really picked the wrong planet to rape. After all, not only do we have vast oceans, but we have water vapor in our air. I'm surprised the aliens didn't walk around in full-body protective suits.

And if they're going to try to use our planet's natural resources, why not start with our moon? It has very similar mineral deposits compared to the earth.

UPDATE: Another good point brought up by the Timberites is how the aliens broadcast unencrypted on VHF-band radio. Even us puny humans have better schemes than that.