brings us... Apple Modifies Software Update for Windows:

Safari now occupies a place in the 'New Software' box, but continues to be offered to all Windows iTunes users. Even still, Mozilla's Asa Dotzler believes Apple should not leave the software checked by default.

Dotzler is absolutely right. The checked by default move in Software Update to install new software is the same sort of logic as the "undeleteable" Internet Explorer icon on Windows.