[ian@huth]

NTL customers aren't really bothered by the cap for two reasons.
1 The vast majority of them do not know that there is any suggested limit on their usage of the service
2 Most of the ones that do know of the suggested usage limit just ignore it and continue doing what they like with their connection.

There are two possible scenarios for NTL to enforce a cap.
1 Customers usage of the service impacts heavily on other users and the integrity of the systems.
2 NTL want to make more money out of customers by providing two levels of service on each tier, one capped, the other unlimited.

It could be that NTL reduce the prices, particularly on the 1 (1.5) Mb tier and strictly apply a cap whilst at the same time offering unlimited usage on each tier at a premium price. What you have to remember is that the vast majority of customers never get anywhere close to the current suggested usage limits and NTLs thinking about caps will be influenced by how the majority of customers use their connections and how many customers would breach or be near a cap.