Nothing wrong with parking aids, I'm sure there's quite a few people here who don't have the privilege of there own driveways and have to make do with parallel parking in the street where others park how they want and don't leave enough comfortable room for others, and some need to park two wheels on a kerb aswell...
Had a golf mk5 before the seat, that was easy as the rear window was pretty much flat so where it ends is where you stop, with the leon (mk1) the rear window is very slanted so that alongside the 'high rear' can be an arse to creep up to someone elses pride and joy
I'm sure theres two kinds of parking aids aswell, one is a constant beam with the ignition on and the other only actuates when reverse is selected, not sure how one of these is affected if someone is parked right up your cakehole when you get in, does the first one identify this obstacle already or does it wait for something else to enter the 'beam area' before it then alerts you?