An Apple Authorized Service Provider told the site that it appears to be a bug in the sensor that detects when the lid is being opened. This has led to numerous replacement devices as it was unclear whether software or hardware was to blame.
One user was able to re-create the problem by pressing the power button then immediately clicking on the touchpad causing the machine to freeze.
An Apple Support representative confirmed that a fix is in the works and should arrive with the next OS X Mavericks update, likely 10.9.2. Notably, OS X 10.9.2 beta 4 fixes part of the issue by requiring a 0.5s or greater press of the power key before anything happens.
"The new power button behaviour makes it impossible to accidentally activate sleep when you intended to press delete, which is a great improvement!"
Betas of OS X Mavericks are being released with little time in between suggesting the upgrade could arrive soon.