Some culinary books and, for example, this Wikipedia article, state that adding alcohol (usually spirit) to dough, it will prevent the dough from soaking oil when you deep-fry it. Does it really work? And if so, why?
Yes, it is probably true to a small degree, but irrelevant.
In any deep fried food, the rapid expansion of water as it vaporizes pushes the oil away from the surface of the food, preventing it from immediately penetrating during the entire frying period.
While alcohol may not have the same 1700 (IIRC) ratio of expansion in volume that water does when it goes from a liquid to a vapor, it will still offer some of the same effect.
The thing is, most oil that penetrates deep fried foods does so after the food is removed from the oil bath, as it cools. Alcohol in the dough would not prevent this.