Back in the wild and wooly
days of Prohibition
, the story goes, crooks
who robbed smuggling
trucks of their loads of illegal whisky
would order the driver
s to "Stick 'em up high, Jack!
" (or sometimes just "Up high, Jack!
Because of this habit, they were called highjackers, then hijackers, and presto, another word entered the English language.
Another rumor has it that they pretended to be friends of the drivers, calling out "Hi, Jack!" in order to get them to stop, but I don't believe it for a minuite.