this is a classic example of fuck around and find out.

Trump addressed the press a little while ago on this topic and claims he's not issuing any refunds until courts force him to. He chastised the Supreme Court for not telling him what to do about refunds, and essentially pleaded helplessness to do anything about it until he fights more lawsuits and rulings demanding specific action are issued, musing something to the effect of "I guess that will take another couple years".

He further claimed that this ruling puts his tariffs on a more certain basis(?!) because now he'll use different statutes that have been solidly litigated already (... so why weren't you opting to use those in the first place, if it's truly better? You didn't need to wait on this ruling to do that!) and that the only effect this ruling will have is a brief drop to ~10% across-the-board tariffs while they do the paperwork to bump them back up again under these other statutes. He repeatedly characterized this is good news for his tariffs, while also complaining extensively about the court and insulting the justices in the majority.