I am inclined to think that German management would have gotten some surprises when faced with how the UAW would act had the union been voted in.
On that point I agree, but looking at the impoverished quality of American automakers for a long time, caving to the UAW to the extent of running their business into the ground, versus German management, I would expect VW to be able to deal better, as well.
It has been pointed out here that VW pays their non-union workers in Tennessee more than UAW workers. So in that sense, they took away the single most significant aspect of unionization.
And my guess is that there was more than appeared on the surface, of VW's openness to unionization.