Where does the money currently come from? Take $1000 of each monthly salary and put a "UBI" sticker on it. Everybody currently employed now gets $1000 UBI for the total price of nothing.

For a person earning $3000+ per month nothing changes, except that their salary now reads $2000+ (same money to spend etc.). For a person currently earning $1500, negotiations with their employer will be different because the salary reads only $500 and losing out on just 1/3 of your income while looking for a new job is doable (if still painful).

But what about a person currently working a job but earning less than $1000? This person doesn't exist because of the "B". But what about a person earning $1100, won't they simply stop working? No, again "B" and never happened in any of the trials done thus far.