I think a little clarification is needed here. The fact that either FOX or CBS has a single game does not mean that all of their markets receive a game at 1 pm ET. (And this time of year, FOX or CBS may be carrying a live sports event in addition to a NFL game.
Thus, for those of us in the eastern and central time zones, we have to deal with late games more often than not since both FOX and CBS have figured out that the late game overruns help their ratings and often suppresses NBC's SNF ratings a bit. Since overruns seem to help TAR's ratings for some reason no one's been able to explain and this is the third year we've had that phenomenon, I don't complain too loudly.
On a related note, the CBS Eye-lerts link now goes to the sign up page again, so anyone who wants the Eye-lert directly to their e-mail can sign up for it. Note that you have to have (or create) a user account for the CBS-related websites in order to sign up.
http://www.cbs.com/eye-lerts