Sometimes I ponder events in recent decades relating to the sale, and use of Marijuana. I see many similarities. But that is whole other subject.
The word bootleg refers to the part of the boot above the instep. Presumably this was a handy place to carry illicit alcohol in days gone by. From this we get the colorful American slang term: bootlegger, one who smuggles that booze. (Today the term is also applied to bootleg music recordings, video, etc.)
From my family stories it seems that alcohol was easily obtainable if you knew the right people. And apparently most people who wanted to know, knew the right people. Spirits, wine, and beer were flooding across the border from Canada and Mexico without any customs tariff or duty being paid. Law enforcement had to be vigorous to try to stem this tide of imports.
My (long-deceased) family members lived on a major route coming into the US from Canada. For some reason (!) they were carrying a case of bootleg booze in their car. My dear sweet mother, at that time a small child, was told not to tell about the box she was sitting on in the back of the old Ford Model-T. If interrogated she was to tell the police that “I’m just playing with my doll.” Oh my! Innocence lost! She became a de facto criminal! Those were the days.