The cost to a manufacturer of a product return is significant: they have to pay the return shipping, shipping back to their warehouse, cleaning, repackaging, and outbound shipping. Often times retailers fine manufacturers for high return rates. Plus, inventory is taken off shelf such that it may miss seasonal cycles (like Christmas or trend cycles). What’s great about this strategy is that the impact of each individual becomes real and significant, at no expense to that individual. If you spend $100 on items then return those items, you lose no money. However, Trump loses $15-20. If you spend $1000, that causes $150-200 in in lost revenue. If 1% of the people that voted against Trump participated, that would cause $150,000,000 in costs, and more than enough economic pressure to cause retailers to drop the brand. Tie up business assets and they’ll atrophy. So will Trump’s pocket book.