With a Swiss passport and the place of birth being Switzerland, nobody will ever ask them.
If they are asked if they have other citizenship, they can always say Germany - end of the inquiry.
If they are asked if they have other citizenship, they can always say Germany - end of the inquiry.
No, you just don't have to say it, you have a swiss passport and that's it.
https://www.irs.gov/businesses/corporations/foreign-account-...