You don't need a flatbed to overcome a fuel kill switch LOL! Fuel kill switches have been along for as long as electric fuel pumps. Every car thief knows how to bypass them. Very easy to run power straight to the pump. The same can be said for the starter and the ignition. In the How-to section there's a write-up on how to put a kill switch on your main relay. The main relay controls so many things that you can't pinpoint the problem and you can't bypass it in one, two, or even three steps. Also, it's virtually foolproof for you to cause any damage to your car if you don't know what you're doing when wiring your kill switch.
Not all switches in the car lend themselves easily to being used as a ghost kill switch. To use it as a kill switch, you have to be able to easily isolate it from the circuit it's intended for, and it needs to be a simple on/off and not a momentary push button, variable resistor etc. Not that it's impossible, but it gets more complicated than it's worth. So hazards, turn signal, dimmer are all out. AC, Cruise, Radio Acc power, headlights, horn, etc are all good choices.
No matter what switch you use, you'll need a SPDT 20 to 30A auto relay. Never attempt to send the full power of your kill circuit through the switch or you'll burn the switch and in many cases you'll melt your dash wiring. You cut the circuit you're killing and connect one cut end to 30, the other to 87. To enable the relay, power has to pass across 86 and 85. So depending on whether your switch is negative or positive switching, the switch will be on either 86 or 85 and whatever it needs, power or ground will be on the other side either 86 or 85.
To make the horn sound if someone tries to start the car w/out hitting the switch, you simply wire your horn to 87A. Make sure 87 is connected to the ground side of the circuit you're killing.
This probably sounds like Greek to most of you guys but that's how it has to be if you're not specific on what circuit you want to kill and what switch you want to ghost. I used to make specific write-ups but I found that everyone will EXACTLY duplicate the example I give instead of working it out and then making it their own. So it's worthless. The main relay kill write-up I did is something everyone can duplicate and it will still be effective (notice I left out the details about where to mount your aftermarket switch).