In many states, open-container laws only apply to single-serving containers. No worries in Delaware though, we don’t have an open container law for cars (passengers can drink, not drivers).
I completely agree that growlers sales won’t make sense for many liquor stores. Space, setting up taps, keeping draft lines clean, training staff are all complications for the store. But nobody is forcing the store to do this either. This is legal in NY, but I know of only a few places that do it (actually, only one).
I’d hope that any store doing this would only offer craft beer that isn’t available any other way. I’d be pretty disappointed if this were legal and someone offered growlers of 60 Minute IPA. It would really be for stores that want to showcase a great selection of beer.
The stores in AL that sell draft to go also sell liquor and sixpacks. I don’t see it being an issue at all. These places do a really good job and you can buy beer by the quart, half gallon or gallon. The distributors in the area have deals with establishments to maintain taps and keep lines clean. The tops of the container is shrinkwrapped or taped before leaving building.
You can also do this with un-finished bottles of wine from restaurants (in some areas). I think they are supposed to seal it up somehow other than just jamming the cork back in, but I do know it’s legal to take home/away from the restaurant. How the police would deal with it if you got pulled over is a entirely different question and not necessarily related to the legality of the packaging.
With the space requirements and hassle of draft to go, I have to think that the establishments selling it would have to be pretty dedicated to craft beer.