Just a thought for those with carbs.
Apart from wiring in an inertia switch I've also wired in a separate cut-off.
This means I can run the carb. dry after use reducing the likelehood of unleaded fuel gumming up the carb. if it isn't used very frequently.
I assume this isn't a good idea for injection systems due to priming issues.
Cheers, Pewe

If you have used a Rover inertia switch you can pull the button up to cut it off.

If it's hidden away it makes a decent anti-theft device as well.