https://www.theverge.com/2017/9/20/16340460/apple-ios-11-control-center-wi-fi-bluetooth-tricking-users

Apple’s new Control Center in iOS 11 is a lot more fully featured, with a customizable layout and a number of new added controls accessible with Force Touch. One aspect of it that may have, at least at first, appeared like a big plus is now proving to be a bit of a security and usability problem: the Bluetooth and Wi-Fi controls.

In iOS 11, Apple lets you disconnect devices or disconnect from networks by toggling off those two buttons from within the Control Center. Those buttons do not, however, deactivate those features entirely, Motherboard reports. Instead, Apple leaves both running in the background to keep certain things intact, like the file-transferring feature AirDrop, geolocation services, and communication with a paired Apple Watch. This is a change from how these buttons have worked in the past.