The NAACP is threatening to protest at South Carolina's highway rest areas as part of the civil rights organization's ongoing battle against the Confederate flag.

Sometime this month – the date has yet to be announced – the civil rights organization plans to post "border patrols" near state lines to remind incoming tourists of a two-year-old boycott.

"We're asking people not to visit South Carolina, not to vacation on Myrtle Beach, or Hilton Head or Charleston, until they do what's proper by removing the flag of the Confederacy from positions of sovereignty in our state," said Dwight James, executive director of the NAACP's South Carolina Conference of Branches.

Sending protesters to welcome centers would be the National Association for the Advancement of Colored People's most aggressive tactic yet in its boycott of South Carolina's tourism industry - an industry that supported the group's original crusade to remove the Confederate flag from the state Capitol dome in Columbia.

"The allies feel somewhat betrayed," said Ashby Ward, president and CEO of the Myrtle Beach Chamber of Commerce.

The Myrtle Beach group was one of 40 tourist development organizations that successfully lobbied state legislators in 2000 to move the flag from the dome to a place of "historical significance."

Deciding a new location for the flag was no easy task. Lawmakers had to balance the objections of many black constituents, who regarded the flag as a symbol of slavery, with the concerns among many white Southerners who considered it a symbol of their unique heritage.

Lawmakers voted to move the flag to a 123-year-old Civil War memorial, which shares the Capitol grounds with other historic monuments, including one dedicated to African-American history.

Many black legislators and constituents applauded the compromise. But the NAACP continued to object, insisting the Confederate flag had no business anywhere on state property.

"The definition of 'sovereignty' changed," said Ward. "All of a sudden, it's not the Capitol dome, but the blocks and blocks of land surrounding it. In effect, I think they won the battle, but then changed the rules."

South Carolina Attorney General Charlie Condon said he will sue the civil rights group if it sends protesters to welcome centers and rest stops. "It's not a threat, it's a promise," he said.

NAACP leaders insist their demonstrations would be protected under the First Amendment, since they would take place on public property. But although there is no legal precedent for blocking protests at welcome centers, Condon said restrictions on newspaper sales and other activities at rest areas have held up in court.

"First Amendment rights and protection do not extend to all government property," Condon said. "We certainly think it's inappropriate to have these demonstrations at rest stops, which are dedicated as places of rest and relaxation."

Tourism development officials believe the NAACP's "border patrols" would have a minimal effect on South Carolina's $9.1 billion tourist economy. But in a state that prides itself on hospitality and civility, some fear a prolonged boycott will damage South Carolina's image.

"There is a perception of South Carolina being a land of barefoot rednecks, and that will probably be perpetuated by this," Ward said. "It's unfair and unfortunate, but will underscore the perception some people have about what we're all about."

Jonathan Serrie joined Fox News Channel (FNC) in April 1999 and currently serves as a correspondent based in the Atlanta bureau.