Contractually, you are required to adhere to the General Terms and Conditions:
11.1.6. use any service in any manner which could damage, impair, overburden or disable the service or interfere with any other party's use or enjoyment of the service;
This means you can't use the internet in a way that interferes with other users experiences. More on this later, but as a general term of the contract it is allowed to vague specifically for the purposes of a catch-all mechanism to prevent abuse of the service.
11.2. Should you engage in any one or more of the above activities, which shall be determined in MWEB's sole discretion and which decision shall be final, then MWEB shall be entitled, without
prejudice to any other rights it may have, to:
11.2.1. without notice, suspend your access to the service concerned;
Again, a general term that permits MWEB to boot you at its sole discretion if you violate the previous terms. Obviously they can't boot you unfairly or arbitrarily, but only if you violate one of the terms outlined in its terms and conditions. One of these is "overburdening" the service, another is outlined below.
12. ADSL Acceptable Use Policy
12.1 You will only use the ADSL Service for purposes that are lawful and for which it was designed.
Clearly the shaping of certain protocols and shaping generally is a "design" of the service, and as a result use that bypasses this "design" constitutes a breach of contract and MWEB has every right to terminate your agreement, even without consultation.
12.2 You will not use the ADSL Service, directly or indirectly, in a way that:
12.2.8 in MWEB’s sole discretion constitutes abuse of the ADSL Service or of MWEB’s systems
12.2.4 interferes with any third party’s use of the ADSL Service;
Again, it is clear that these specific portions of the contract deal with exactly is being debated now. Either one, or both of these breaches may have occurred. Bypassing the shaper, constitutes an abuse of 'MWEB's systems'. Obviously. Furthermore, someones incessant downloading all day every day (and it would appear from MWEB's posts that these people were doing so by running their lines at full speed, in violation of MWEB's shapers) constitutes an interference of a third parties use of the ADSL service.
12.8 We reserve the right to manage our network in order to optimize its efficiency for the benefit of all our subscribers. We may take any other action we deem appropriate in order to help ensure the integrity of the network experience for all subscribers.
This clause applies to a multitude of MWEB's services, though as it appears in the ADSL specific section of the contract it should be viewed in that context. Clearly this clause would refer to a 'system' as referred to above, that limits or 'optimizes' the network for MWEB's clients: the dreaded shaper. Interference with that system constitutes a breach, and a termination is inevitable. The fact that MWEB may take any necessary action to ensure the integrity of the network only demonstrates that they have the power to boot you if you threaten that integrity, by bypassing the shaper or sharing your connection for financial gain, you are undoubtedly attacking the integrity of the network.
12.12 If the ADSL Service is used in a way that we, in our sole discretion, believe violates this Acceptable Use Policy or any of our rules or limitations, we may take any responsive actions we deem appropriate. Such actions may include without limitation, temporary or permanent removal of content, cancellation of newsgroup posts, filtering of Internet transmissions, and/or the immediate limitation, restriction, suspension or termination of all or any portion of the ADSL Services or your account.
The final nail in the coffin, which I believe wouldn't hold in a court as it is too vague and overtly powerful (especially with the imminent Consumer Protection Act). However, if one is to entertain this clause for a moment we can understand that MWEB is serious about maintaining the product at acceptable levels, and that they may take any action they deem necessary to protect that asset.
Even if the final clause is severed from the agreement, surely people can at least see that MWEB is well within its rights to exclude you from the service, and must additionally fulfill its obligations to its other clients in maintaining a usable service within acceptable standards. Your abuse of the systems extend to both bypassing the shaper and using the product in a way unlike that for which it was designed and for this you should be excluded from enjoying the service or migrate to a service better designed for your needs. That is all. I shall comment no further on this discussion.