can you leave a bar with alcohol?!
Depends on if they have an "off sales" license or not.
As for the bottle - technically it's theft, but then again you broke the law by trying to leave with alcohol - Is it worth risking them taking you to court over a bottle.
PS: In the UK it is NOT that usual for pubs to supply take out containers. A few do but they have to have an on and off sales license, not just an on sales one.
The answer to your question depends on where you are. In England it is not only permitted but quite normal. Many pubs supply 4 pint containers that customers can fill with a cask beer of their choice t take away.
I assume that this problem occurred in some US city.
What she did is illegal. As for getting the bottle back, probably not. Call a lawyer.