Isn't the rackspace cloud their cut-rate service? would they have called if it was a slicehost (premium price) customer?

Still, I think it is a good idea, and one I ought to implement in my own service. The problem is that we all hate dealing with the phone, but that sounds to me like a lazy answer.

On the other hand, really, if you are an abuse problem, honestly, I don't want you as a customer.