Long gone are the days when someone heard a house alarm and the local police office on duty would be there within a flash to investigate it. With many alarms attached to the mains electrics of a home, unfortunately they often go off following a power cut or electricity surge. This has made us as neighbours, reluctant to act up on hearing an alarm going off in case it is accidental.
Ideally if you want to have a house alarm, you have it linked up to a security company or the police who will be instantly notified when the alarm goes off. If this happens and it is false you can call the police or security company and advise them, otherwise they will often send someone out to check it.
This costs more than your standard security alarm, but if no one responds to a house alarm, it makes sense to have the proper system fitted.