The pledge was the idea of student leaders who wanted to give some weight to the US university's 12-year-old honour system at a time when cheating — including Internet-aided plagiarism — is said to be on the rise on campuses across the country.

The standard pledge says: "I pledge on my honour that I have not given or received any unauthorized assistance on this examination."

So far the pledge has been given a lukewarm welcome, with some students saying professors regularly ask for it, while others seem to forget.

Some question what exactly it means to sign the pledge. For example, professors cannot refuse papers that have not been signed.

And, unlike oaths that are taken in court or appear on legal documents, there is no penalty for violating the pledge other than those already imposed on people caught cheating.

"It's never been clear to me whether it's mandatory," said Josh Korr, a graduating senior from College Park, Maryland, and a columnist for the student newspaper. "You've never been allowed to cheat before. I don't know how the pledge would add to that."

Others said the only deterrent to cheating was the one that already existed — the fear of getting caught.

However, many faculty members say the pledge gives them peace of mind.

"I'm under no delusion this will stop everyone from cheating, but it places a higher hurdle on the students," said professor Kate Campbell who required students to sign a pledge even before the campus adopted one. "They can't claim they were never confronted with this."

Some note, in fact, that there has been an increase in the number of reports of cheating since the pledge took effect — 39 more charges than last year. Pledge advocates attribute the rise to growing awareness and concern for academic integrity on campus.

The notion of academic honour is hardly new to Maryland. In 1990, the university adopted a student-run honour system, joining 100 other US colleges with similar measures.

The administration gave students the power to investigate and judge alleged cheaters, a show of trust they hoped students would respond to by respecting the honour code.