Re: very appealing for a small ISP.
Might not be appealing, but does it provide the service you promised to your customer? I'm paying my ISP for the connectivity, not Netflix.
If the ISP wants to modify our contract to include a Netflix peering surcharge, because the cost of that connection is disproportionate to the rest of the service (use whatever method of determining typical non-Netflix user you want) that's fine and I'll evaluate the value of that new contract. After which I'll decide whether paying the charge or canceling Netflix. BUT I expect you'll be adding similar charges for other heavy broadband usages such as video Torrent downloads as well.