Ellen Schoetzau was betrayed two years ago, and the culprit was her former assistant principal.

After moving up the ranks to run his own campus, he went after one of Schoetzau's prized teachers at Mantua Elementary School in Fairfax County. The new principal, learning that this teacher had recently moved near his school, recruited her with a quality-of-life enticement: a shorter commute.

Schoetzau doesn't blame the teacher. But she has unkind words for her fellow administrator, who bypassed Schoetzau in his headhunting efforts and never told her he was interested in a member of her staff.

"I just don't think it's professional," she said. "I don't want someone messing with my school and I don't want to mess with anyone's."

Many principals say they, like Schoetzau, adhere to an unofficial code of conduct that prohibits raiding a colleague's teaching staff.

But as schools scramble to fill an unusually large number of teacher vacancies this summer, some principals say that the practice of luring instructors from other schools within the same district is a fair tactic.

"I think you always feel an obligation to bring the right people in," said Geoffrey A. Jones, the principal at Thomas Jefferson High School for Science and Technology in Fairfax County. "I'm sure there's a time when every principal sees a good candidate [within the district] and thinks about how to bring this person on staff."

About 8 percent of Fairfax teachers move to another school in the district in a given year, Fairfax school officials said, and Montgomery County's turnover rate is about 6 percent. No Washington area school systems keep figures on how many such transfers are initiated by principals, but several administrators said they have been on the losing end of a recruitment drive.

It usually isn't money that persuades teachers to make such a move. Within the same district, teacher salaries differ only by years of experience and level of education, which wouldn't change if a teacher switched campuses.

Instead, principals who woo other schools' teachers will offer them the chance to reach a professional goal. A new campus could mean a department chairmanship, an appointment as faculty adviser of the school newspaper, or the chance to teach in a full-day instead of a half-day kindergarten class.

Student achievement also can be a factor, some teachers said. In an era of high-stakes testing programs, a teacher at a low-performing school can ease job pressures by going to a school with higher scores.

Some parents praise principals who are aggressive in seeking to recruit the best staff possible, saying that it should be no different from what happens in the private sector.

"If my principal knows that this teacher has a good reputation for getting the job done, if this is a really good teacher, then sure, let's go for it," said Rosemary Lynch, president of the Fairfax County Council of PTAs.

But many Loudoun County principals said the practice is frowned upon in their district. Raiding a colleague's teachers, they said, creates a domino effect in vacancies and disrupts planning if a teacher departs unexpectedly.

"There's kind of an unwritten ethical code that you don't go stealing somebody else's staff," said Paul E. Miller, the principal of Banneker Elementary in Middleburg.

Principals said they must consider not only their school, but the staffing needs of the entire Loudoun district, which has been growing 10 percent annually and will open four new schools at the end of this month.

As principal of Blue Ridge Middle School, the only campus for sixth-, seventh- and eighth-graders in Loudoun's western flank, Joseph L. Mauck Jr. said he is approached frequently by teachers interested in transferring to his school.

When he does have an opening, he said, he looks at his waiting list of candidates at other Loudoun schools and then contacts their supervisor.

"I call the principal up first and say, 'I'm interested in this person. Will it hurt you?' " Mauck said.

When Principal Nancy E. McManus announced that she was leaving 27-year-old Lovettsville Elementary to open a new school in Ashburn, she encouraged anyone interested in working there to apply through the district's transfer process. Two teachers made the move to Cedar Lane Elementary.

McManus said she didn't recruit individual staff members. "It's just not common practice to do that," she said.