Not bad at all.
Although I find it hard to believe anyone would get that worked up over aliens mining outer moons for ice, especially once it had been established that they had no weapons. Even if they filled their entire ship with water, it would amount to a fraction of a percent of the mass of Europa.
My take on it would be that their technology would have a lot of Earth corporations and scientists drooling on their shoes, and probably firmly squatting on any attempts at military endeavors.