[Chrysalis]

"There is a difference between making a small loss on a few customers with high usage and having to spend thousands on the network to prevent those few users from affecting other users on their UBR."

Thousands in a one off investment can be considered a small loss, these heavy users I doubt make much difference to peak time demands for NTL they probably make more of a difference to external bandwidth costs and quiet time demands, I am sure UBR's need only be upgraded to cope with peak levels of traffic.