An actual good use case for tariffs.

Not really.

You can tariff a single company.

The normal response to a company importing illegal products is to seize them at the border, destroy them, and, optionally, send the importer a big fine. This is already an established process.

> importing illegal products

What's "illegal" about these products?

> send the importer a big fine.

And that gets paid?

> This is already an established process.

And has it ever been used for /civil/ software GPL violations?

Or you could just prevent the goods from being sold, rather than making the American tax payer foot the bill for that company's crime.