One of the provisions of using open-source code is that you have to honor the license the code was provided under, which usually means supplying the source on demand. From what other people have observed, Asus may not have properly fulfilled its obligations under the GPL to release all the source code used to build the Eee PC's proprietary hardware drivers. Or maybe someone just goofed.
The whole thing's documented over at Cliff Biffle's Cliff Hacks Things blog, where he's also posted some useful scripts for the Eee in general (such as how to unload and reload the Wi-Fi drivers with a script). He downloaded the source archive, all 1.8 Gbytes of it, for the Asus Eee PC, and found to his dismay that the package is far from complete. The asus_acpi kernel module, for instance, was the subject of a great deal of change -- none of which appears to be part of the source package or released back to the community in general. (There are other changes and omissions, but that was one of the most glaring.)
What happened? If I had to hazard a guess, I'd say the source code archive that Asus put together was done in haste, or at least put together by someone who simply forgot to include everything that needed to be there. It's entirely possible the omissions were calculated and selfish, but given the scope of the omissions I'd wonder if it was just slipshod work and nothing more.
I can see why people are suspicious, though. One of the hazards of open source is that anything you release under an open-source license can be easily exploited by people who don't give a hoot about open-source licenses. They see free software with no strings attached and make a grab for it. They count on no one looking to get away with such things, but in a world this large and with this many people who just love to hack stuff -- like Cliff Biffle! -- the odds of getting away scot-free with a perfidy like that are slimmer each day.
I also should say that incidents like this shouldn't be construed as an argument against the GPL or open source as a whole. No more so than, say, the fact that a car can be stolen is an argument against ever owning one regardless of what kind of neighborhood you live in. But it is an argument for vigilance.
Either way, there's something here that needed to have light shone on it. As far as motives -- well, for now, I'm filing this one under "Never assume malice when incompetence will do just as well."