i'm not sure i'd even pay for parking sensors if they were optional.
I wouldn't have paid for the sensors if they were an option. Its a hatchback, not a tank, if you can't park it then find a bigger space or buy a smart car.
We don't know what the real reason is, but if I was in your boys shoes I'd of taken it off my order straight away. Yes, it looks cool on the screen but after a month it'll become the norm. And you can't see the camera pop out at the back as you're driving, so whatever! Honestly, I would be feeling that its holding up my order and I'd get shot straight away. If it was the PP or Nav then I'd wait, but for a camera gimmick? No way - take it off! Just my opinion of course.