Haven't seen it in here yet so...
Was searching in the shop manual last night and found the fuel pump system is much the same as previous RX-7s. If you did want to install a fuel pump on-off switch, there is a connector on the bottom of the dash (drivers side) or it may be in the kick panel - wasn't too clear in the manual. It has a white wire with a red stripe on it. That's the one to switch. If you put mating connectors on the switch, you wouldn't even have to cut a wire!

I can't think of any reason for this (security is taken care of by imobilizer system and flooding by throttle to floor shutting down the injectors), but there it is for info. anyway.

 

God help us if people seriously think they need a fuel-cut switch to prevent flooding...

 

Just easier to use the old model than develop a new one?