Examples of how a college or university would unfairly discipline a student would be too many to count. To give a brief overview it could be because the student is falsely accused by a school, say an academic misconduct case. A professor, for example could falsely accuse the student of some kind of academic misconduct. He could claim that the student plagiarize or collaborated with other students. The student may very well not have done so, but could find themselves brought up on false charges.
In terms of the process itself, schools, unfortunately, they do not regard in many instances and accuse student's rights and interests. They can either, say, rush a disciplinary process or just not allow a full and fair process. The parties involve the decision makers can have conflicts of interest, they could have bias. People that serve in these roles can be poorly trained even when the expectation would be the complete opposite.
There's various reasons of due process concerns and other procedural issues and irregularities that could take place during the course of a college disciplinary investigation and conduct proceedings. There's too many examples to count. Having an experienced attorney advisor that's been down this road before, would be able to help protect your interest and rights. They'll know what to do in terms of responding to the school, what's appropriate, what should be taking place, what shouldn't be taking place. They can help you navigate what can be a difficult process. They should be involved as early as possible if you're facing any kind of misconduct allegation at your college or university.