As mentioned in the above toot yesterday, the UK government are going to be scaring the pants off half the country at 3pm today with an emergency alert test. If you have a hidden phone you don't want someone finding out about, turn off emergency alerts in that phone's settings or turn the phone off. Otherwise it's very likely to make a loud noise once the test commences. Edit: Going through the replies suggests it's best to turn the SETTING off and NOT just the phone.