Newport Harbor has about 10 students who fall into the exception, said Principal Michael Vossen.
Costa Mesa High School has five students, said Principal Phil D'Agostino.
Estancia High School has 11 students with the exception, said Principal Kirk Bauermeister.
Corona del Mar High School Principal Tim Bryan said his school doesn't have any students who fit that situation.
Back Bay/Monte Vista High School couldn't be reached on Wednesday for comment.
Some students don't see the de facto policy as equitable.
"I think they should pass (the exit exam), because it's kind of unfair that I passed," said Back Bay/Monte Vista senior Daisy Marin, 18.
Board policy states that commencement is for students who have earned a diploma that cannot be obtained, in accordance with state law, without passing the exit test. There are some exceptions for students with disabilities.
According to board policy, "High school graduation ceremonies shall be held to recognize those students who have earned a diploma by successfully completing the required course of study, satisfying district standards and passing any required assessments."
Despite walking, students will not get a diploma until they pass the exam, said district spokeswoman Laura Boss.
"It's always been our practice," Boss said. "It's nothing new."
Graduating Back Bay/Monte Vista senior Kzamir Patelski, 17, said he doesn't know why students would want to participate in commencement if they weren't getting their diploma.
"Why walk?" he asked.
Thirty-year school Trustee Judy Franco said past policies were different at each school.