If this program causes inflation because the cost of it is untenable, then $12K can quickly become worthless. Supply and demand are laws of nature, you cannot escape them. If the economy suffers from lack of productivity as a result of this program, and money must be printed in excess of what goods and services are being produced...then nominal payouts matter not. Hyper-inflation is a real possibility and has ruined more than one empire in history.
The argument that a UBI would cause a significant amount of inflation continues to be nonsense. Necessities do not have perfectly inelastic supply and would not be consumed in significantly larger amounts than they are already. The large majority of the US population already has access to food, shelter and medicine and pulling the remaining <10% of people into the market is not going to cause hyperinflation. There is a pretty good guess that it could relieve a lot of the existing regional high prices by making it more attractive for people to move into lower cost of living areas and use the UBI to offset the lower average wages there, until enough people have done so to bring down the already existing high costs in major cities.
