[Blas]

Interesting that this topic should be brought up again. I was just discussing the issue of cut-off switches with another person a few days ago.
I believe you will find that most cars will continue to run after flipping off a power cut-off switch, weather positive or negative cable installed.
WARNING: IF YOU DECIDE TO TEST THIS STATEMENT, BE ADVISED THAT IF YOU DISCONNECT THE BATTERY WHILE AN ALTERNATOR EQUIPPED CAR IS RUNNING, THE ALTERNATOR AND IGNITION BOXES CAN BE DAMAGED BY A VOLTAGE SPIKE.
This spike can be avoided by giving the alternator output a safe path to a ground when the switch is turned off. What happens on most cars with cut-off switches installed is that car will continue to run on the alternator output voltage. I have found but not yet tested, a cut-off switch that looks to eliminate this serious issue. Pegasus Auto Racing Supplies sells a switch (#4430 Master Battery Switch) which I think solves this problem. The way the instructions are written (by Pegasus) is a bit confusing but after talking to their tech today it all makes sense now. This looks to be a good upgrade for everyone that might need to stop a running engine in an emergency and wants to minimize collateral damage to the electrics. For those who use the cut-off as a security device, there is no need to change it out.