Geoffrey, this whole thing is a non-issue publicity stunt. We already cleared that up in our book "Atari Inc. - Business Is Fun" released last fall, going by direct interviews and actual internal documents.
There were never thousands of ET games buried in Alamorgodo, that's a myth that sprung up later and was also never once mentioned by the actual press articles of the time. The dump there was simply a clearing out of Atari's Texas manufacturing plant as it transitioned to automated production methods and a focus on personal computer manufacturing. It had previously been one of the main plants for manufacturing of game cartridges and other hardware, and game manufacturing was being moved overseas to China.
As part of the transition the unused cartridge stock of a group of titles (not just E.T.), console parts and computer parts were all dumped there in New Mexico. It was covered in detail by the Alamogordo press at the time, and is just such a non-mystery that I'm surprised by all this.