Starter kill relay, can I wire it to the fuel pump

Is this fine to do with a normally closed relay?  I've got the DEI 6000ESP installed in my 88 300ZX.  It is much easier to hide the relay and wires if I can wire them to the fuel pump, or even another 12V line that needs power to start and drive the car.  I have a Engine Control fuse on the drivers side kick panel.  I could very easily clip this wire, and no one would have any idea what wires were cut.  The only reason I'm asking the question, is I don't know much about relays, and whether it is safe to have a constant 12v+ running through them.  The starter would only be for a few seconds at a time, whereas my idea would be constant. 

           Thanks   Logan