It is very disappointing that, after lock screen there are some options we could still use for example we can make the phone silent or vibrate. It is vey risky as if we lost the phone and the thief quickly make it silent then what is the use of this ...
It is needed for greater security, if your phone lost by mistake then anyone can just make it mute and we will not find it by calling our number as the phone is already mute.
