My ISP Charter communications doesn't care, I have had weeks where 18gb-20gb per day download is normal for me and no complaints whatsoever. I still download easily over 2Gb per day even without getting any files as I get a lot of the YouTube type sites linked to me which also max out your connection if you ever notice so between that and getting headers for certain groups you can easily keep your daily download ratio pretty high. I use multiple connections to each of my servers and max out my 5 Mbps connection. I have been using them for over 3 years now.
Although, I know friends in my town who got letters, from Charter, for downloading Sopranos a couple of years ago and Superman Returns recently but they used unsecured bit-torrent to get these files. The letter simply stated that they should delete said material if they have it on their computers as it was an illegal download.
So they do pay attention it seems but looks more like its probably due to the RIAA/MPAA going after downloaders through their ISPs.