No fermentation should take place unless you have A LOT more fruit than . . .
a lot more fruit than liquor. Alcohol is a product of fermentation: think of it as a yeastie-beastie waste product! When the alcohol gets to a certain point, the fermentation stops 'cuz the yeast is unable to grow (or is dead from the waste products). Of course some yeast can tolerate higher alcohol around than others can.
Since you are macerating fruit in a distilled liquor (which is much more alcohol-concentrated than an undistilled product), the alcohol acts as a preservative, keeping yeastie-beastie fermentation at bay. . . (Or so I understand!)