Brake Lines Blown While Towing with Toyota Tundra!!!!

I have experienced this twice on different vehicles, both times from leaking brake lines. In both cases, the brake pedal went to the floor and really scared me. Yes, I had some braking left, but it felt like very little. Half of the reservoir still had fluid. This is a very realistic scenario, and it is frightening. It is disappointing on a 2 year old vehicle, though. In my situations, the vehicles were more than 10 years old and had over 130K miles.