[Kevin Sevcik]

That would provisionally work, yes. The issues I'd want thoroughly addressed before I'd use it:
1. How reliable is it under FRC service conditions? We're talking pretty exciting bumps and crashes, and available voltage dipping into the 9V range under heavy current draws. And you have that diode dropping .7V of your available voltage for energizing your coil. It'd be unfortunate if the coil dropped out under those conditions when an unmodified Jag would hum merrily along.
2. I don't have the Jag schematics up at the moment, so I can't say that one of these will work. You may need two to completely disconnect the H-Bridge to actually protect everything important.
3. You do realize you're proposing to slap a 1" cube into the Jaguar's innards? The Horribly Oversized and Oppressively Bulky Jaguar? If this turned out to be the solution, I think I'd take a leave of absence from CD for a year to save myself the howls of outrage.