Call it an object lesson: When two teachers were suspended after a student died on a high school field trip, their colleagues decided to stop sponsoring extracurricular clubs, outings and competitions.

That upset students, about 300 of whom walked out of classes Tuesday at the Yvonne A. Ewell Townview Center and marched on Dallas School District headquarters.Townview teachers voted last week to stop sponsoring school outings and competitions until colleagues Lee Bloomfield and Marsha Evans are reinstated. Teachers say the district's policy on field trips is vague and that teachers risk their careers if an accident occurs on a field trip.

The two were leading about 50 students on a trip last January to mountainous Big Bend National Park when 14-year-old Colt Perryman fell 7,800 feet to his death.