Disillusioned: If you object to the first resolution I offered for the reason you stated, ignore it and use the second resolution. I don’t think it is a strong objection but even if you do the objection doesn’t impact the second resolution I gave.
Your last paragraph doesn’t negate anything I proposed in my second resolution. Suppose a mosod decided to give away $5,000 to a random Yid living in Lakewood, no purchase necessary, they just want to generate publicity for their mosod. Your logic would suggest that whoever won the $5,000 would have to automatically give it all to maaser.