A police officer one told me to be honest there is really nothing you can do to prevent a thieft from taking a car or a motorcycle. Alarms, Chain locks etc... just really add a level of time if a thieft really wants your ride he or she will find a way. So lets continue to make there job alot harder.
I only say this because my uncle was a victim of bike theft, he had just got back from a ride and went inside to take a shower. To his surprise when he came back out for a ride his bike was gone, a nieghbor told him he saw 3 men back a pick up truck up to the bike picked her right up and placed it into the back of the truck and pulled off.
It was a sad day he had a really nice Honda CBR with custom whield shield that illuminated neon green at night it was sweet.