To take (lunch) to work, typically in a brown paper bag.
To take (liquor) into a public establishment, such as a restaurant, that does not serve alcohol.

brown bagger
A person who brings his or her own supplies, as in The architects of the new office designed a space for brown baggers to eat lunch. The term originated in the 1930s in Britain for very serious students who carried their books about with them in brown briefcases or bags. That usage crossed the Atlantic within a few decades. However, in America from the 1960s on, it has primarily been used for persons who brought their own liquor in a brown paper bag, either legitimately or surreptitiously, to a public place or restaurant not licensed to sell it, or for those who took their lunch to work.