During testing of microelectronic dice, the dice are moved by pick-and-place mechanisms and advanced to further processing. A plurality of dice is often tested in a die tray that includes several die pockets. After testing, the die tray is removed and stacked for further use with dice that are up-line from testing. Occasionally, a die is not removed from a die pocket of a die tray, and tested devices are stacked on top of untested devices, which can result in “escapees” of untested devices.