What is the cellphone popcorn trick?

I saw this video on YouTube where people use four cellphones (eight actually) to make the cell phones pop popcorn. The video was used in a headphone commercial for CardoSystems whose website only features a segment of the video.

From About.com: Alex Boese figures there must be a heating element hidden under the table. A physics professor consulted by Wired.com concurs, suggesting there may have been some sneaky editing involved as well.

Louis Bloomfield, a physics professor at the University of Virginia said "In a microwave oven, energy excites the water inside popcorn kernels until it turns into highly pressurized gas, causing the kernels to pop. If mobile phones emitted that much energy, the water in the fingers of people holding them would heat up. It would hurt like crazy," Bloomfield said.

So there's a trick.

The most absolutely absurd explanations (but pretty much ONLY explanations I found) were people who actually hooked up microwaves to their living room tables.

Seriously? Sounds like a good way to grow a third arm.

This is so dumb I can't even keep writing about it.