It happens. My wife, a Zambian national, got a jury summons for our county. We had to go through some rigamarole to get them to understand she was not a citizen, and not even in country. I don't think there is any vetting at all. They probably think "No one wants to serve on a jury, so if they have a good reason not to, they will let us know." The way it resolved was so tenuous, I'm not convinced it won't happen again. This is King county, heartland of the Beautiful Blue state of Washington and welcome mat for homeless street shit.