Is non of my business but why not charge your client for the extra bandwidth. I had the same problem and did just that and the customer didn't even complain.
I'm a reseller and find that customers are willing to pay for me to set up a wordpress site and I just need to know if you will shut me down for to much traffic to thier sites.
I don't think it'll be right for me to continue selling this service if later on you'll tell me that I'm causing a...