I also don't know why he chose to hire a car instead of taking a taxicab. It may have been poor judgement. It may have been the proper choice under the circumstances. I don't have enough information to form a judgement or enough interest to find out.
But I do think I understand why some folks have their knickers in a twist over this. They know that bad things can come out of the back of limousines.
Updated: Limos make somebody else think about John Gard, too.