Even if it's only plausible, many countries have laws on the books preventing the sale of weapons to countries under suspicion of committing genocide. I know that the UK has such a law. UK arms export licensing Rule 2c states: licences must “not grant (licenses) if there is risk …of a violation of international humanitarian law”.

So already with the ICJ's plausible ruling, many parties and countries open themselves up to lawsuits if they continue business with the Israeli military. Japan has stopped working with Israeli Elbit systems because of this, and it also led to the US pushing through their major arms deal with Israel, including 25 F-35 and 25 F-15 fighter jets, to be singed the day before the ICJ delivered their preliminary verdict.