They are not supposed to be doing that, for shame Comcast....
But then they are putting their ass in their hands when a customer goes to dial 911 and they cant get through and then that customer sues when a family member dies or the house burns down. I have seen a court case like that for VOIP phone before, they customer claimed the service provider didnt verify the service was working, etc.. It can go either way.
Some areas it takes a while to get a tech out, here it takes about 4-5 days on average, but lately its been more like a week. All depends on how busy they are and how many techs on call.
That reminds me, two tech in my area were "let go" so its really hard to get the guy here now.