Some courts seem to have adopted an extremely pro-prosecution attitude about what it means to voluntarily “abandon” fingerprints or DNA samples. FourthAmendment.com reports on a California case, People v. Thomas, where a defendant stopped for a DUI consented to a breathalyzer test. Because he did not wipe his saliva off the mouthpiece before handing it back to the police officer, he was deemed to have voluntarily turned his DNA over to the police.
I doubt that most people think about refusing to hand a breathalyzer device back to the police or think to ask whether they could wipe it off, first. The court’s reasoning on “voluntary” here is just so out of touch with any “reasonable person” standard that I am floored.