Plagiarism isn't always on purpose. Sometimes, students simply do not know how to cite their sources. That is why it is vital for teachers to instill proper referencing skills early on in the classroom. However, there are those students who do copy maliciously, and professors are cracking down on the crime with quick zeros and sometimes more severe punishment, such as expulsion. Online professors, though, find their virtual classrooms almost free of plagiarism, which is a surprise to all in the education field. These professors say that students in a traditional classroom are more likely to cheat than an online, because perhaps they do not know the guards and tricks that even traditional teachers have. Some professors believe that students in fields such as sports, nursing, etc, are more likely to plagiarize because they feel they do not need to be able to write to effectively perform their job.