So I have been seeing these a lot lately and it has been getting extremely annoying.
When you join Xbox Live you accept a contract, Code of Conduct/Terms of Use. Which states in it that modifying the service of Xbox Live is against the Code and by breaking the code it can and will get you banned. You agreed to these terms.
Here are some of the terms stated in the Code of Conduct/Terms of Service

You must not use the Service to harm others or the Service. For example, you must not:

use the Service to harm, threaten, or harass another person, organization, or Microsoft;
damage, disable, overburden, or impair the Service (or any network or Authorized Device connected to the Service);
resell or redistribute any part of the Service or access to the Service;
use or attempt to use any unauthorized means to modify, reroute, or gain access to the Service;
use any automated process or service (such as a bot, a spider, periodic caching of information stored by Microsoft, or metasearching) to access or use the Service, or to copy or scrape data from the Service;
obtain (or try to obtain) any data from the Service or related hardware, except the data that we intend to make available to you; or
use the Service or related hardware to design, develop, or update unauthorized software.

That is saying that modifying anything on your account to access features you should not normally have is against their Code of Conduct.

Now here is another part of their Terms Of Use and Code of Conduct.

You may only access the Service with an Authorized Device or by logging into your account via the World Wide Web. You agree that: (i) you are using only authorized software and hardware to access the Service; (ii) your software and hardware have not been modified in any unauthorized way (e.g., through unauthorized repairs, unauthorized upgrades, or unauthorized downloads); and (iii) we have the right to send data, applications or other content to any software or hardware that you are using to access the Service for the express purpose of detecting an unauthorized modification. You must not attempt to disassemble, decompile, create derivative works of, reverse engineer, modify, further sublicense, distribute, or use for other purposes the Service, any game, application, or other content available or accessible through the Service, or any hardware associated with the Service or with an Authorized Device. If you do so, we may cancel your account and your ability to access the Service, and pursue other legal remedies. We may take any legal action we deems appropriate against users who violate our systems or network security, this contract or any additional terms incorporated or referenced in this contract. Such users may also incur criminal or civil liability.

We reserve complete and sole discretion with respect to the operation of the Service. We may, among other things: (i) restrict or limit access to the Service; (ii) retrieve information from the Authorized Device and any connected peripheral device used to log onto the Service as necessary to operate and protect the security of the Service, and to enforce this contract; and (iii) upgrade, modify, withdraw, suspend, or discontinue any functionality or feature of the Service, any game or other content available or accessible through the Service, or any hardware or software associated with the Service or with an Authorized Device, from time to time without notice. We may do so by the automatic download of related software directly to your Authorized Device, including software that prevents you from accessing the Service, playing pirated games, or using unauthorized hardware peripheral devices.

Saying that if you are caught modding the Xbox they have the right to upgrade(Connect Jtag to Xbox live so it gets un jtagged), modify(change it back to normal) withdraw, suspend or discontinue any function of the service, console ban, account ban, IP ban etc.


So to sum things up, Every time you mod a game, mod an xbox etc.. you have a probability of getting banned! So stop asking cause it can and will happen