The first clue that Billy Valentine has a well-defined contrarian streak was his Yankees cap, which he wore as he ducked under the orange and white balloons affixed to D.C. parking meters and entered Farragut Square yesterday.

The balloons -- part of the Baltimore Orioles' Annual D.C. Summer Fanfest -- were clear signs that the team wants to continue staking a claim to the Washington area's baseball fans. But one of the four signs displayed by Valentine, 17, and his brother, Steven, 14, was just as clear:

"BOYCOTT THE ORIOLES."

The brothers, from Alexandria, said they wanted to issue a call to arms to fight the long-established tendency among fans of embracing the closest major league franchise. Instead, they want fans to embrace the possible relocation of the Montreal Expos to Northern Virginia or to the District.

The reaction among thousands of orange-clad, autograph-hunting Orioles fans was, Billy admitted, "mixed." Some gave them thumbs up; some gave them dirty looks. A lot suggested they weren't ready to switch their allegiance just yet. "The Orioles are my favorite," said Peter Brosnan, 13, of Falls Church. "I just like them because they're my home team. The Expos -- they aren't very good."

For years, the Orioles have targeted D.C. area fans with events like yesterday's, a tradition that began in the mid-1980s when the team opened an official Orioles store on 17th Street NW and ordered the word "Baltimore" removed from the team's media guides. The strategy to embrace the nation's largest market that lacks a team of its own has been successful, and it was evidenced by the 4,000 fans that the Orioles organization estimated showed up for yesterday's event.

"What that kid [Valentine] doesn't understand is that we lost the Senators twice because people here wouldn't show up for the games," said Orioles fan George Bryant, 52, of College Park. "I grew up in D.C., and I'd go to those games and see 500 people in the stands. Then I'd go to Memorial Stadium [in Baltimore] and see 20,000. History repeats itself."

But first, history must wait on word from Major League Baseball, which is expected to decide the fate of the Expos this fall. Before that decision was postponed this summer, the news was expected to come Aug. 18 -- the same day as yesterday's fan appreciation event.

"I think it was kind of [gutsy] for them to schedule this on this day," said John Rauber, 46, of Potomac, a lobbyist who stopped by the event on his lunch break at a downtown firm. "I have four sons who are big fans and like the Orioles. But I think they'd switch if Washington got a team, because they'd have a home team to root for."

Only a small minority said they'd do the same. For the most part, the fans who waited in snaking lines for the chance to get the signatures of such players as Rafael Palmeiro, Melvin Mora and Javy Lopez were not about to abandon their loyalty. But many said they probably would become two-team fans, rooting for the Orioles in the American League and the other team in the National. As for the interesting possibilities of interleague play, most said they couldn't imagine rooting against their current favorite players.

Rick Dempsey, who played for the Orioles for 12 seasons and is now the team's first base coach, said he hopes events like yesterday's foster loyalty among D.C. fans by encouraging connections between stars and supporters.

"I remember the buses that used to come up from D.C. to Memorial Stadium, and those fans were crazy," Dempsey said. "We don't want to let that go. It's not that we don't want [the D.C. area] to have its own ballclub, it's just that we enjoy having them with us. They're part of the family."

Blake Gwinn, 23, is the kind of D.C. resident that some opponents of a D.C. team point to when they assert that the city is composed of transplants from other regions and wouldn't be able to loyally support a team. The Kansas City native moved to the District and became an Orioles fan four years ago. He estimated he attends 25 games at Camden Yards each season.

"If there were a team in D.C., I definitely would frequent that," said Gwinn, a real estate agent. "I might still go to Baltimore, too, but I think it would depend more on the performance [of the Orioles] than it does now."

The Valentine brothers said they were so excited about the prospect of a local team that they attended a news conference last year held by a group wanting to bring baseball to Northern Virginia and volunteered to help. Billy has even dressed up as a mascot, "NIMBY: The County Board Chicken," when Arlington County asked to withdraw from consideration.

After encountering a few adversarial fans among the crowd, Valentine said that a lot of them seemed to have traveled to the District from Maryland.

"I hope they all drive back in rush hour so they can see what it's like for us to go to a game in Baltimore," he said.

Kathy Welsh, 44, of Germantown shouts during a cheer for the Orioles at the fan celebration. The team said 4,000 supporters turned out.Sam Stockton, 7, of the District gets ready to pitch to his brother.Linda Allworth, 7, of Herndon hugs one of the Orioles' biggest stars, the Bird, at the D.C. Summer Fanfest. Players came to sign autographs.