Research for a university project. - Bike locks

How confident would people feel locking their bike up with a much much smaller lock, but if tampered with, a very loud "rape-alarm" style siren activates from somewhere within the bike?

It's been done before but the alarm is always in the lock, not in the bike, so you can just ride the bike away..

2 points

1. Is a lock still a lock if it isn't there?
   
2. What would stop the thief still riding away with it when they're so brazen these days as to cut locks in front of people in daylight!