Saying it would prevent Benjamin Pedro Gonzales—Alameda County, California’s “most violent offender”—from exposing anyone within spitting distance to HIV, Superior Court Judge Jeffrey Horner ordered him to don a mesh hood during his trial last November. The judge expressed fear that Gonzales would “spit his HIV-infected saliva at anyone near him.” Along with the hood, which resembles a beekeeper’s bonnet, Gonzales had his hands chained to a chair and his feet affixed to the floor. Commonly called a “spit sack” by police and highway patrolers who use it to guard against TB and hepatitis, the hood was created two years ago by California’s Eagle Gear.

Gonzales, 39, a former ranch hand on trial for allegedly butchering an employer, has a history of violence, including stabbing his lawyer with a pencil and slashing an inmate with a razor blade. “He was trying to exchange bodily fluids,” testified Deputy Sheriff William Borland at a pretrial hearing, fueling fears that Gonzales would “use his saliva as a weapon.”

“The defendent is extremely manipulative, inventive and devious. He is able to exploit even a momentary lapse in security,” said Horner, whose rush to judgment obscured one fundamental transmission fact: The saliva of someone with HIV poses virtually no health threat. “Wearing a hood is very different for someone with HIV than for someone who is negative. It’s a form of humiliation that brands you as contagious,” said Judy Greenspan, of the HIV in Prison Committee of California Prison Focus. “It sends the message that anyone who comes in contact with Gonzales can get HIV through saliva.”