Edinburgh University Students' Association has called for a full review of what constitutes plagiarism following university action against 117 students found guilty of "unacceptable collaboration".
The first-year computer science students had their marks reduced after email evidence revealed that "significant parts" of a practical exercise had been copied.
Graeme McAulay, president of EUSA, said: "When 117 students are accused of cheating, there has clearly been confusion in the class over what kind of cooperation between students is allowed. The course organisers must take responsibility for that confusion."
Business consultant Jeremy Roe, father of 20-year-old student Henrietta Roe, said his daughter was contemplating suing for defamation.
Miss Roe, who is dyslexic, had relied on other students because she found the course confusing and poorly taught, he said.
"The students worked with each other quite openly. The issue is that none of these students believe they were cheating. They believe the university was wholly aware of what they were doing," he said.
Nick Saunders, director of the education law group in the national legal firm Eversheds, said allegations of plagiarism were on the increase.
"The answer must be to make it absolutely clear to students from the outset of courses what the ground rules are. Students are being encouraged to work together, which is admirable, but universities must make it clear whether that is permissible in relation to assessed work."
Edinburgh's course guide says students can obtain help and advice for practicals from tutors, demonstrators and students, but must "resist any temptation to indulge in simple plagiarism".
Mr Roe has written to Edinburgh's principal, Sir Stewart Sutherland, protesting that at no time did anyone attempt to speak to his daughter to explain the allegations against her, outline the evidence, or hear her response.
A university spokeswoman said the extent of the problem, and the summer vacation timing of the investigation, meant the board of examiners had been unable to interview the students individually. Students could submit grounds for possible reconsideration of their case.
"We don't believe the teaching in the department is below standard in any way," she said.