I don't agree. It's not an issue of straight jacketing programmers. It's an issue of reminding a user they are incurring an enormous bill for no reason. A simple "Hi, we see you're using X widgets but your traffic would allow you to reduce this to Y widgets. If you'd like to do that, here's a link. If not just ignore this email." That would solve the problem with very little effort. It would keep people forgetting and having a heart attack, getting pissed and leaving. It really doesn't matter if it is the customer's fault if it causes them to leave with a bad taste in their mouth.