said by Comcast User :They will call you BEFORE your service will be cut off to ask you to curb the usage. However, the call would be well too late for you to actually be able to fix it, since it will be usually about two weeks into the billing cycle, so you will be probably cut off anyway if you are way above the 250 GB. What I have seen on the forum here if you are in the 400 GB range you are already marked for disconnection.
I just called Comcast to see what my usage has been for August. I spoke to four different people including two managers and no one could tell me what my month-to-date usage has been. Comcast said that if I exceeded the cap, someone would probably call to let me know. I asked Comcast if they would call before my service was cut off or after my service was cut off, they weren't sure.
Just my opinion based on empirical observation.
Treason is a matter of dates