Border guards in the Schengen area in Western Europe screen foreign travelers in a database called SIS. Someone in violation of Schengen duration stays might (I could be wrong) have their passport flagged in the SIS in the form of an alert or notification.
Do Schengen member countries share SIS data or alerts with other countries (e.g. USA, Australia, etc)? For example, if you try to enter the USA, will an American border guard see that you have outstanding passport violations in Europe?
Do Schengen member countries share SIS data or alerts with other countries (e.g. USA, Australia, etc)?
No, they do not.
It should be noted that not all alerts are travel related.
For certain other areas, mainly of a criminal nature, missing persons etc. (which are also alerts), agreements can be made for a restricted access under the condition that the data protection laws are respected.
REGULATION (EC) No 1987/2006 (on the establishment, operation and use of the second generation Schengen Information System (SIS II))
Article 39 Transfer of personal data to third parties
Data processed in SIS II pursuant to this Regulation shall not be transferred or made available to third countries or to international organisations.
Per Wikipedia, in addition to the Schengen countries, Romania, Bulgaria and Ireland have access to the SIS.
The UK had access as well before Brexit, but this is no longer the case.
Information is not shared outside Europe (in the broad sense, EFTA rather than EU).
However, you should never presume a third country will not know or find out about previous immigration related issues. There could be other ways to find out then having access to SIS, so don’t omit such issues if asked about them in visa application processes.
Also, in the most extreme cases, there could be Interpol notices (probably not for a simple overstay, but for more serious stuff like document forgery for instance that is probably possible).
