Do you think car (or van) thieves even know how to use a manual choke or double clutch?
Well, let's say they are Classic Car thieves. A fuel shut off would give them a false sense of security until the carb runs dry. A hollowed out potato in the tailpipe can put in "Valet Mode"
A long time ago they tried to steal my 60 vette, they towed or somehow moved my wifes 76 vette out of the way and had my vette in the street when something scared they away. I also chained my car to my house until I had my garage built. And got a carry permit- 9mm at my bedside, great dane = good night sleep.
In the past I used one of those red plastic shut off keys inline on my negative battery cable. Just put the connection in a hidden place and take the key with you. Of course you'll have to wire your stereo directly to battery to keep presets but with an 8track it doesn't matter!
three on the tree is the best theft prevention to the younger theives of all time. i put a night switch in under the dash which cuts power to the electric fuel pump. the van will only go about a block if its shut off.
My line lock does not need power to stay engaged. I set it and the park brake for four wheel brakes locked. you would have to dolly it to take it away. I also have the flashing blue LED fake security light. My three spd shifter converted to opperate the automatic is confusing. If you pull up on it like everybody does to shift out of park; it will become disengaged, so it will stay in park and the lever falls loose.
If I really feel insecure about where my van is I can also pull the fuel pump and crank fuses. It will not turn over or start at all then.
I have a remote starter kit I will be installing. It has a security feature for ignition and fuel pump cut off activated by the key fob and a relay that shuts the engine off when you hit the brake, if the start procedure hasn't been done right..
I use a heavy-duty latching relay controlled by a key-fob wireless remote to remotely disconnect the battery. I also have a normally-closed 12v fuel cut-off valve installed. Even if you could figure out where the big relay was located and then bypass it, you still wouldn't have any fuel.
This setup also doubles as a safety mechanism. If I hit the remote, it kills the battery and fuel flow in one shot. I also have a collapsing circuit set up with a thermal fuse in the doghouse that will activate the relay and kill both the battery and the fuel flow in the event of a fire.