Security is not an all or nothing, absolutist concept. The idea of secure being the 1 to the insecure's 0 doesn't work. Security is a spectrum of options. A level of security that would easily deter a casual car (Deuce) thief would barely slow down a skilled thief. A higher level of security capable of thwarting even a skilled thief would not prevent a theft by a determined thief who's specificly targetted your MV.
The idea here is defense in layers. Make it so your theif, be they the neighborhood punk or a determined operative for a competing nation-state, can't just stand in one spot and defeat measures one, two, and three, and be gone.Make them go to one place to defeat that measure, then somewhere else to defeat that one, then a third place to defeat another. Make each anti-theft measure different.
First layer, a locked garage with multiple sensors and video surveillance.
Circumvented by any means any home security system gets circumvented.
Additional measures could be an OC fogger in the garage that has to be specificly deactivated by the garage alarm, else it operates on its own.
Second layer, a set of keyed locks on all the points of entry as well as the ignition.
Circumvented by a brick through the passenger's side window and hotwiring skills or swiping the keys from the house after circumventing the security system there, not to mention these things can be push started with no electronics at all.
Additional measures could be additional thermoplastic film layers bonded to the stock windows making them far more difficult to just bash in, also more safe in a collision.
Third layer, an auxilliary fuel cut off valve under the hood.
Circumvented by knowing the truck's standard anatomy and running the fuel line to find the valve.
Additional measures could be one fuel cut off valve under the hood and one behind the fuel cell. They found one doesn't mean they'll look for the other.
Fourth layer, an auxiliary ignition interlock switch under the dash.
Circumvented by the same hotwiring skills as layer two, but if the thief is relying on a key, this could just throw them enough to make them give up. Or get up under the dash and trace the ignition wires and discover the hidden switch ... somewhere that has to be pressed at the same time as the start lever has to be thrown.
Lots of mass produced civilian vehicles have very simple, rudimentary alarm systems that understand that certain events cannot preceed certain other events. A simple alarm such as this that will start caterwalling if, say the ignition switch is thrown without the key in the ignition or the doors having been opened, etc. etc. will both detect theft attempts and deter their success.
Fifth layer, a radio remote engine kill switch.
Circumvented by discovering the hidden box or the extra engine mechanicals and "disrupting" them, or if you kept the keyfob on the same keyring as the Deuce keys.
This is often part and parcel of even basic after market car alarms. If the alarm goes off, it actively interferes with the operation of the engine. A more advanced alarm talks two-way with your keyfob, and if the engine is running and the system fails to hear a radio responce from the keyfob X number of times, it kills the engine, and these engines already have a method of killing the engine on the dashboard. Adding some mechanicals for the alarm would be pretty elementary.
Sixth layer, screw the engine kill and make it detonate a small charge under the driver's seat.
Circumvented by the same methods as the fifth layer if discovered by the same tracing of cabling from the fourth layer, but it would be so much fun if it worked.
Okay, if you're not privy to access to claymores or lumps of C-4 and detonators, if you put an OC fogger in the garage, put one under the dash too.
As your security gets deeper and deeper, the outer layers get no harder to circumvent, but having breeched them, the existence of more work will eventually make a thief decide that the work ahead is greater than the work already done and cut his losses.