to be honest in all actuallity it could work because alcohol is composed of simple sugars,simple sugars are derived from in vodkas case carbohydrates,the alcohol would kill off some bad bacteria and the plant may absorb it and deconstruct the deconstructed and break it back into its original components,witch would boost the plants metabolism on the molecular scale.
u would have to do like 2tbls per gal h2o to be on the safe side
but the other aspect is the plant may see it as a poison and as its absorb,the plants defese mechanisms will be hit by basicly in medical terms it would be like a stroke,but it would be a plant stroke bc it couldnt use it and it shutdown and destroyed valuable matter.
try it as an experement if u got the room and time,who knows it may be a benificial find.
ps try it as a foliar aswell bc the alcohol may kill the bugs bc as the mist hits the leaves,bugs will often come out and drink and when they drink the concetration of alcohol,a funny thing happens,they surcome to alcohol poison,thus killing them