My insurance company had a discount for alarms but it required an alarm system that had an annual checkup/contract. Discount, ooh, £10, cost of yearly check £80. Bit of non-brainer especially since the insurance company required me to switch the alarm on overnight downstairs even if I was in the house (thus waking up family when I get up early for work switching it off).
Only experience of alarms going off is a tale my mate told me. Someone set off his alarm, police came round, nothing to see. Scrotes cam round 30 minutes later setting alarm off again but no-one batted an eyelid thinking it was still a false alarm as they cleared the place out.