USA - Alcohol in a brown paper bag

So why do liquor shops use brown bags at all?
Much of the myth surrounding alcohol in brown bags has to do with a law in effect in many (not all) states in the USA that prohibits liquor shops from selling alcohol without packaging it in some form.
This practice may serve to give the purchaser some privacy when buying alcohol.

Brown bags may conceal open containers
The reason for brown packaging may also be an attempt to circumvent open container laws. This is because in most states in the US, it is illegal to drink from or possess an open container on a public pavement, in a car park, on the front steps of your home, or in a parked car.
Whether or not you have your alcoholic beverage in your bag, however, does not protect you from arrest in most states.

So public drunkenness should not be your bag
Even though an open bottle of vodka in a brown paper bag can protect you from open container laws - no brown bag will save you from a public drunkenness charge. So if you show up drunk in public in any of the 50 US states, the brown bag can't help you either....only a lawyer can.