Although the practice of reducing alcohol in wine (as opposed to travailing in the vineyard to give birth to wines with lower alcohol) is far from uncommon today, especially in wine-producing regions where grapes are over-enthusiastic in their production of sugar or where grapes are picked so late they might be more attractive in a fruit cake, trying to get people to admit their complicity in the alcohol-reduction plot is rather like trying to persuade lawyers to divulge information about their clients.
If we take a look at the processes involved, maybe this conspiracy of silence will make more sense...