https://www.schneier.com/blog/archives/2014/12/the_limits_of_p.html - "The next time you call for assistance because the Internet service in > your home is not working, the 'technician' who comes to your door may > actually be an undercover government agent. He will have secretly > disconnected the service, knowing that you will naturally call for help and > -- when he shows up at your door, impersonating a technician -- let him > in. He will walk through each room of your house, claiming to diagnose the > problem. Actually, he will be videotaping everything (and everyone) inside. > He will have no reason to suspect you have broken the law, much less > probable cause to obtain a search warrant. But that makes no difference, > because by letting him in, you will have 'consented' to an intrusive search > of your home" >