Forgive me but doesnt white labeling implies some sort of written agreement preventing white labellee (?) from stealing those codes? from my limited understanding white labeling is just licensing the product sans branding?
And usually you would want lawyers who are on your side of the table to review, if not write up the agreement, not the lawyers that the prospective business partner brings (unless they are a well known and trusted entity whose creds are sky high, like in the case of YC)
Also, a legal document, especially dealing with international business is only as good as the country with the weaker and less robust legal system. I am originally from India, a country with a democratic government, relatively decent free will and an independent judicial system, and still it is far from being as robust as that in the US. Now there are many countries where the legal system is no where as independent as the one in India, so you can make a guess as to how much protection the legal systems in those less 'free' countries will give in spite of having a 'legal document' in place.
This also happens to be the reason why I am trying to set up a company in the US first for my next start up, because it still offers one of the best protection for businesses, while simultatneously being one of the best markets.