[iLoch]

I wouldn't consider it a ticking time bomb. They provide a (false) guarantee to the end user that other users won't be able to capture whatever you sent beyond the time given for them to view it. (This is false because anyone can take a picture of their phone's screen.) Users would understand the very reasonable difference between users having general access to this "expired" data vs. the police. Most people should expect that the police have special privileges in this case, and I don't think there'd be any backlash if this became broader knowledge. Their promise to their users is to provide them with the secrecy of a "secret note", not government proof secure encrypted messaging.