I guess living where you do parking ain't too much of a problem - try finding a parking spot down in the London area and its like winning the jackpot, if you can squeeze the car in that is - hence the sensors become very useful - only wish I had them at the front too.
Oh, and I agree the feeble beep sounds ridiculous in the ZED - my wife's Honda makes a much more horny sound (well, at least the sensors beep does!)
Don't think you understood the posts from Tim and me - the reverse gear beep in the JDM has nothing to do with parking sensors - it's just a warning that you are reversing!
Edit - but I appreciate the point you are making about the benefit of sensors for parking. I try to avoid close parking whenever I can, and a pal who has a much loved MX5 vies with me very often to see who can be the best at what he calls "defensive parking". This usually means parking at the furthest extremity of a car park, even if it is pissing it down - not appreciated by the better half as you can imagine!
On a similar note, I often see a sunset Z parked at the next station along the line from me when I am on the way into Glasgow for work. He (or she) always parks at the point of the extensive car park furthest from the platform.