I guess you are probably right, better not say it, i am starting to thinking of putting a secret switch because those cars are easy to stole. I have an idea of using a headphone jack as a key. Maybe after finishing with the engine.
I don't think a headphone jack is a good idea as it probably be able to handle the current. You could use one of these. I used to have one fitted on my battery but lost the knob that you unscrew. I have just ordered a new one as you brought up the subject and they are very cheap plus you need access to the bonnet to it, so it's adds a little bit more protection but doesn't prevent someone who is really determined.
You simply unscrew the knob and take it with you.
http://www.ebay.co.uk/itm/like/2319...3D710-134428-41853-0%26rvr_id%3D1151131775481
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