Nope, not usually. If someone wants to steal the truck, they will. A little black control module and a siren will only keep them at bay for a few extra minutes. People usually dont pay attention when a car alarm is going off, it happens constantly and just doesnt draw attention unless its the middle of the night.
Aside from the convienence features alarms add (keyless entry, window up/down, remote start), it is more of a placebo effect for people. They think that an alarm system will give them some extra anti-crook forcefield around the vehicle.
The pager ones might be good to have if you park in bad areas frequently, but other than that its all about being lucky.
