I'd say good luck with that.
To acquire BAT at scale fraudulently from rewards will likely cost more than it's worth, and to convert it into fiat will require going through KYC / AML processes AND avoiding being flagged by Brave's fraud analysis.
I don't think they've published anything on fraud analysis, but what their research team has published is indicative of the calibre of Brave's team: https://brave.com/research/