Brakes Failed problems of the 2010 Jaguar XF

I purchased a 2010 Jaguar Xf last summer and believe there is a serious safety issue. Shortly after taking delivery, the power brake assist failed when I was entering a freeway. Fortunately, I had tapped on the brakes to avoid a car in the lane I was entering. I immediately realized there was very little braking power. If I had needed to brake at a higher speed on the freeway, it could have been disastrous. The serious issue is that this failure does not trigger a 'brake failure' light on the instrument panel. Therefore no warning. I limped home and had the car towed to the local dealer. The problem was that a plastic tube which carries the engine vacuum signal to the brake unit had become detached, thus no power assist for the brakes. The dealer replaced the plastic tube. I contacted Jaguar headquarters to inquire about a brake failure warning alarm fix for this problem, but they informed me that 'this was way it was designed. No fix possible. '.