Any ballots that are cast under same-day registration are cast as provisional and will go through the full verification process if the election is close enough where those ballots are necessary.
Source: actually ran a fucking election precinct. Non-citizens aren’t casting ballots illegally.
They literally just charged someone in Philadelphia for illegally voting in every federal election since 2008. Non-citizen, ordered deported back in 2000 but still in the country.
There's not been a reliable audit to show the extent to which this happens (probably not enough to affect even local elections), but to say that it isn't happening is just a lie.
I'm not talking about same day registration. If you are on the rolls and proof of citizenship is not required to register, then how do you as a poll worker know the person on the rolls is a citizen?