Palm Scanners in MD Schools Raise Privacy Concerns

Associated Press reports that Carroll County (Maryland) students are now having their palms scanned to pay for their lunches. What caught my eye in their report was that about 20% of parents have reportedly declined to participate in the program because of privacy concerns. That strikes me as a somewhat higher percentage of refusal than we’ve seen for other cases of using biometrics for students. Are Carroll County parents more savvy about privacy or is there some other explanation?