"That's not a reason unto itself to conclude that that's a scam Web site, but it is a reason to be cautious, " Swecker said.

CNN: Dubious Katrina Web sites increasing

"The emphasis here is on 'unsolicited, ' things that come in that you didn't -- you have never made contact with this particular charitable organization, " Swecker said.

CNN: Dubious Katrina Web sites increasing

Swecker, the U.S. Court of Appeals for the Fourth Circuit relied on this same language to find that a Virginia rule restricting alcohol ads in college newspapers was constitutional.

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