I feel I should point out that I live in an upstairs flat - my keys are only visible if you are 20ft tall! I also live in a cul de sac full of mainly old people and council tenants - your typical car stealing burglar is going to be looking elsewhere.
I have a really early (A-serial number, non-export model) passive version. That thankfully (for me) has a 42mm nut as I hate Jazz profile necks.
Just something to watch out for, they're not all the same π