After a nearly blemish-free record that culminated in a $3 billion acquisition by Google, Nest today issued a surprising halt to sales of Protect, its gesture-controlled smoke alarm. One of the device’s key features was that you could wave at it to turn it off. Turns out, sometimes people wave their arms around when there’s a fire in the house, too. Thus, as CEO Tony Fadell put it, “This could delay the alarm going off if there was a real fire.” Oops.