Police are checking the doors and waking people up if they can get in
Police in Liverpool have tried to "break into" 3,500 homes to check people are locking up at night.
Officers are testing front and back doors in burglary hotspots in Everton and Woolton and waking residents if the doors are unlocked.
So far they have successfully opened 66 doors and spotted 14 open windows.
In Liverpool North, which includes Everton, there were 316 burglaries in just one month, nearly half the figure for the whole of Merseyside.
Police have said that people who have been woken up after leaving their door open have, on the whole, given a positive response.
One said: "It gave me a terrible shock, but it is such a good idea.
"It has made me much more aware of making sure I lock the door.
"My son had been out and he'd left the door unlocked."
Police community support officers will then visit the property the following day and issue crime prevention advice.
A police spokeswoman said: "Particularly vulnerable premises are 'target hardened' with window alarms, door alarms, locks and crime prevention tools like SmartWater."
Police are also targeting known prolific burglars.
Each suspect is allocated a specific officer and are visited every day until they are either arrested or police are satisfied they are no longer committing crimes.