I don't think I've ever seen someone mention the health risk until now. That is an excellent observation, especially with people transferring things from the original bottle. It is possible to contaminate booze. So someone gets sick from their illicit hooch and they'll blame it on the cruise line's bar staff. You know it would happen!
One of the reasons we do not allow messages threads about how to smuggle booze (besides it being against cruise line rules) is those threads inevitably invite nitwits to chime in. I recently saw a thread on another forum where a booze smuggler justified his conduct with this: the cruise line is "forcing" him into a restrictive environment as far as what he can purchase and the prices he has to pay, and that isn't fair. If that doesn't take the prize for world's worst rationalization, I don't know what would.