I found an interesting study on Engadget that was done to check the effectiveness of foil hats in blocking government "mind-control" radio waves. The researchers found the hats actually amplified the signals instead of blocking them.
But they didn't check all hat designs; only the fez, the classical, and the centurion were checked. Mine is shaped like a baseball cap, naturally. So until someone proves this is ineffective, it stays on!
By the way, does anyone else think the model head they used looks like former US Attorney General John Ashcroft? Another reason why I'm suspicious of the results.