This is a very understandable mistake. First, that radiance doesn't fall off as distance squared is confusing when you first hit a graphics class, and there were no graphics classes with ideal specular reflection then; Whitted was inventing it! Second, the picture with the bug I think probably looks better than without: the fading checkerboard in the specular reflection looks kind of like a brushed metal effect. So it's a good hack!
|Whitted's famous ray tracing image. From wikipedia|