So the question of the evening then is, "Why the Mayans?"
Seriously though, you guys have got it all wrong with the tin foil and paper bags. Studies have shown that brown paper bags are easily ripped, and that tin foil can cause nasty sunburns when placed too closely to the skin for extended periods of time. We aren't quite sure how these different phenomena occur, but we believe that they are offensive tactics developed by the aliens themselves. Those abductees were good for somethin'.
No, you guys need to get with the latest in alien repulsion technology. I'm personally taking orders for my own deflection hat design. Its covered in rubber to absorb the brain-waves in a controlled fashion, and it contains triple layers of both aluminum sheeting and durable, grocery tested bags to liquify the deadly rays on contact. Lined with supple newt skin, these hats come in blue, red, yellow, and green. Since you guys are my friends, I'll cut you a bottom bargain deal of $300,000. What's your life worth?