It's not willful by the users of copilot. Damages would be low since it's easy to show that users have no intention of infringing, and in most cases, aren't aware they're infringing.

If liability sits somewhere, it's with copilot, github, and Microsoft.

A lot of that might come down to bedside manner. Right now, github isn't super-polite to people whose code it used. That's probably a mistake. They'd be a unsympathetic evil megacorp in a jury trial.