People who work bullshit jobs (https://en.wikipedia.org/wiki/Bullshit_Jobs) are already unintentional leeches. UBI would disincentivize that inefficiency. Then those who want to sit on their asses with their $1200 could do so guilt-free, and, in my rosy vision for the world, the fraction who want to do something more fulfilling than making money for "the host" (e.g., FAMAG, Wall Street, I dunno) would be empowered to focus on things that are important to them, and probably to humanity as well.