Kill switch tether for late model bike

I've been trying to find a tether kill switch to take a street bike to the drag strip. It seems most modern bikes need a switch that opens when you fall off. All the 12.95 emgo type switches close when you fall off, and the ones that open are better and start over $30. Anyone have a source for an inexpensive normally closed kill switch? Any other quick ideas?

 

Take a long shoe lace(like for work boots) and a tiny sheet metal screw and screw it to the kill switch button so it will theoretically trip the switch if you fall off. Looks hideous, but should get you through tech.

 

like he said... i've seen one of those tiny little self tapping eye hooks just screwed and glued right into the "run" side of the kill switch. tether some fishing line or whatever and if you fall off it pulls the switch up to the kill side.