I throw bottles in my luggage all the time. And I've done this from many parts of the world ( Japan, India, china, Europe). Never an issue. The only thing to worry about is the amounts for international customs. And of course the airline fees if your bag is overweight. I admit a few times I did not declare it when I returned. No need to declare anything on domestic flights. I fly mostly delta and just wrap it in clothes. I have heard that united requires it to be in a container but I'm not sure. Check your airline's policies.