I would argue that it is not really covert as brown bagging for public consumption is a well known social convention. Most Americans (especially those enforcing

I would argue that it is not really covert as brown bagging for public consumption is a well known social convention. Most Americans (especially those enforcing the law) know or assume that when you are obscuring a bottle with a bag and consuming from that bottle in public, you are consuming alcohol. It is not much more covert than not placing the drink in a brown paper bag.