Every once in a while, admissions officials at St. Lawrence and Clarkson universities receive "tips" on high school seniors, in what they see as a bid by other applicants or parents to sabotage students' acceptance decisions.

The ploys don't affect who gets in, admissions officials say, but they might point to an increased competitiveness to get accepted to college.

Terry E. Cowdrey, vice president and dean of admissions and financial aid at St. Lawrence University, Canton, said that in her time at the college, officials have been sent about five letters or e-mails about applicants.

"Ninety-nine percent of the time, it's sent anonymously, so we won't act on that," she said. "One of the possibilities is that they see this person as competition. They might somehow believe that a student is 'getting away with something,' and that this is their opportunity to blow the whistle."

Sometimes the letters will include a newspaper clipping that refers to an applicant, or a claim that a student plagiarized his or her essay or inflated a list of activities.

Ms. Cowdrey did say that SLU will follow up on tips if someone sends them along with the sender's name and contact information.

"One time we got a Web link to an article about an altercation between two rival high schools after a sporting event. It listed some names who the person said they thought were applying to St. Lawrence. We checked into it, but it did not negatively affect our decision," she said.

The college can't, however, reveal any information about students — even whether or not they're applying — to third parties, she said.

"We have a commitment to confidentiality," Ms. Cowdrey said. "There was one case a couple years ago where a mother called me up and wanted to know whether so-and-so was applying because she thought he had bad character and she didn't want her daughter to attend if he did. I can't even reveal that."

Brian T. Grant, director of admissions for Clarkson University, Potsdam, said that he has encountered a situation like that only once.

"There was what I would call a bizarre incident," he said. "Last year I was on the road recruiting, and a mother happened to be in the hallway at my hotel. Whether it was a coincidence or not, she started to say some unfriendly things about another family that was considering Clarkson. I put zero stock in what she was saying."

Mr. Grant said his staff has never received or followed up on a negative letter about an applicant.

"We promote the fact that this is not a competitive process, that we're just looking for the right students," he said. "We don't have limited slots, so parents don't have to feel like one student is taking their daughter or son's spot."