Honestly it could have been something as simple as a a missed bleed of an air bubble in the brake lines. But this was on a less than 3 yr old car, and its been a while since we last discussed it, & I don't recall if they had any sort of brake service where that would be a possibility - either way after a scare like that, one expects your car maintainer (in this case the dealer) to be open to a bit of diagnostic work - even if only to maintain good relations for future purchases.