In stores yes, but on the Internet, including it in the price makes it easier to bump up prices. Showing the price without tariff allows you to easily compare before / after, and then when you see tariff added to your bottom line order (e.g. on Amazon) it should drive home the point that tariffs are a tax paid for by the consumers (which unfortunately lots of people still dont believe).
I see two items for $5, but when I add the imported one, suddenly it costs more — and Amazon didn’t tell me that ahead of time or give me any way to choose the one without tariffs on the grid/list view.
This makes tariffs more effective because they can’t bump the domestic price to match — while giving customers a negative chock each time they choose an importer for a product.
Right, but they'll underprice just below the floor price for the imported good, because why would businesses leave money on the table?
The choice for consumers won't be "choose between a $5 item and $15 item" it will be "choose between $13 and $15", like I mentioned above.
This doesn't work as easily if the sticker price for the imported good is $5 and the real price displayed at the end of the purchasing funnel. The local business will have to keep its sticker price at $5 to avoid losing customers when they initially compare goods or rely on customers to come back to them once they get faced with the tariff tax, which will also lose customers.