At Mount Vernon High School in suburban New York, the Knights played their homecoming game amid silence, the contest decided in an empty stadium on a Friday morning last month because a hometown man had been shot dead in the city of the team's rival the week before.

At Goldsboro High School in North Carolina last year, the Cougars played their homecoming game to an audience of parents only. Rumors had been flying that kids were planning to fight.

This week, after the accidental shooting of a 17-year-old girl at an Oct. 28 game, Annapolis High School has moved its traditional Friday night homecoming game to this afternoon. At tomorrow's homecoming parade, marchers will reach the City Dock and then just go home. The game will have already been played.

The cherished ritual of Friday night high school football -- hot chocolate, marching bands and blankets under the lights -- has long been as sure a sign of fall as the changing of the leaves. But this season, a series of shootings and stabbings during and after the games threatens to upend the tradition here and across the country.

School officials in Anne Arundel County have rescheduled remaining Friday night games this year for times when fewer people will attend. Games have been played at twilight, on Saturday afternoons and, in the case of today's Annapolis contest, after school on a Thursday.

The changes have not been widely embraced among parents at Annapolis High, some of whom were in an uncharitable mood last Friday after rearranging their lives and fighting rush-hour traffic to attend a game at North County High School that had been moved up two hours, to 5:15 p.m.

"The bottom line is, they're totally blocking parent involvement," said Jan Schwartz, the mother of Panthers linebacker Jon Schwartz, who was seated with some like-minded parents in the visitors stands. "If somebody is going to bring a gun, they're going to do it if it's dark or if it's light."

The kickoff times are wreaking havoc with schedules. Parents have had to take time off from work. Referees have had to shuffle assignments. The new varsity game times have affected junior varsity teams, which now play at odd hours. Coaches are grumbling about lost revenue at the gates and concession stands; attendance was off by one-third at last Friday's Annapolis game.

"I had to get off two hours early to come to the game," said Sheree Brown-Queen, a juvenile probation officer who was at the Annapolis game Friday to cheer nephew Justin Brown, a Panthers safety.

A former Annapolis High School cheerleader, Brown-Queen said she remembers seeing her mother in the stands at every game, and she intends to do the same for her nephew: "It's important to kids to see people there at the game who support them."

There have been 10 shootings and stabbings related to high school football games around the country this fall, according to Kenneth Trump, a Cleveland school-safety consultant who maintains a database of violent incidents at schools.

Most of the violence has occurred before, after or outside of games. Three students have died, all in postgame altercations in parking lots. One was 15-year-old Kanisha Neal, who was stabbed to death in a brawl that broke out between two groups of girls after a Sept. 23 game between Blake and Sherwood high schools in Montgomery County. The others: a 17-year-old male shot after an August exhibition game in Miami, and another 17-year-old male shot outside a mall after a game in Richardson, Texas.

Before this fall, the last fatality at a high school football game was in November 2003 in Sugar Land, Texas, according to Trump's database.

High school football is a magnet for violence, according to coaches, principals and security officials. In many suburbs, the game is the biggest event in town on Friday nights. It draws an audience far beyond the school community, a group that sometimes includes members of gangs. Team rivalries can fuel tempers. A packed stadium provides an ideal stage for committing a violent act and then slipping into a crowd.

"The people who can walk through the gate for a Friday night football game include many individuals who could not simply walk into the schoolhouse in the middle of the school day," Trump said.

Eugene Peterson, an Anne Arundel school board member, called the Annapolis shooting "a wake-up call." He disagrees with those who dismiss the case as an accident. "With kids and guns, there's no accidents," he said. "So let's not call this an accident."

It was definitely quiet when the Mount Vernon Knights played their oldest rival, the New Rochelle Huguenots, said Ric Wright, Mount Vernon's coach. "There was no one there except for the police," he said. Players had to help the referees move the down markers. Mount Vernon ultimately lost, 40-16, despite its theoretical home-field advantage.

New Rochelle students learned their team had won only after the game was over, in an announcement on the school intercom.

"Everybody just kind of looked at each other," said Eileen Fener, 17, a New Rochelle senior who had planned to attend. "Nobody cheered. Nobody knew what to do."

School officials in both Anne Arundel and Montgomery have tightened security in response to the violence. Montgomery had to contend with two deaths within a week. In the second case, a 23-year-old Germantown man was beaten with a miniature baseball bat a block away from a Sept. 16 Seneca Valley High School football game. It is unclear whether either the victim or the suspects in the case attended the game, said schools spokesman Brian Edwards.

Additional police and school staff members have been assigned to remaining games in both counties.

No tickets are being sold after halftime at games in Anne Arundel, and no one who leaves the stadium is allowed to return. Starting most games at twilight means "we're going to be able to look at them and eyeball them as they're walking into the stadium" to better judge who might pose a threat, said Roy Skiles, assistant superintendent of Anne Arundel schools.

When the Annapolis High homecoming game was moved from Friday to Thursday, it was too late to reschedule the traditional pregame parade. School officials have optimistically renamed it the Victory Parade.

And if the Panthers lose?

"That's a good question," said Matt Vollono, 17, the Panthers quarterback. "It puts a little damper on the parade, I guess."

Police investigate a shooting at Annapolis High last month. The school's Friday night football games have since been rescheduled.

Police officers patrol last Friday's game between Annapolis and North County. The game was started two hours early.Slug: aa/foot10 Date: 11/04/2005 Photographer: Jonathan Newton/TWP Neg# 174262 Location: Glen Burnie, Md. Summary: Annapolis @ North County high school football Caption: Anne Arundel County police officers A.R. Slauter (left) and D.P. Jones keep an eye on the crowd as North County hosts Annapolis High. StaffPhoto imported to Merlin on Sat Nov 5 18:09:02 2005Anne Arundel police, from left, D.P. Jones, A.R. Slauter and C.P. Powell watch the crowd at North County High last Friday.