Comcast Cable: 4 Hr ETA time window and STILL late!

I remember having a conversation I had with a fellow colleague 2 wks ago when I had scheduled my Comcast Cable setup for my home.

The Comcast guys said that they'd arrive at my place between 12noon and 4 pm and that if they could not make it on time - then I would get a 20$ deposit to my account.

Well - how many ppl do manage to get that 20$ credit I asked my colleague ... and rephrased that to ... How can anyone have a 4 hr time window, live in the neighborhood and STILL ever be late???

2 wks later - today Guess wat - its 4:15pm today and the comcast guy hasnt yet showed up! Yes - I know - it is unbeleivable.