We have conducted a few minutes worth of research on what consequences other units of government face after they violated the Open Meetings Act.
Here is some of what we found:
-City Council and Mayor indicted on felony official misconduct charges for violating the Open Meetings Act while conducting Peotone Village business (HERE). Case was pleaded down to civil consent (HERE) with a written admission of violation and promise not to violate in the future.
-Lake Zurich Mayor and Trustees charged with violating the Open Meetings Act (HERE) and forced into mandatory Open Meetings training. Alleged violations include "shadow minutes", meeting via email, and others.
-In 1972, Illinois Attorney General Scott wrote an opinion (Page 11) to the Illinois Board of Higher Education's Executive Director, that among others, wrote about the provisions of the Act to ensure compliance with the Act, those are: 1) The ability of a judge to issue writs and other orders to ensure compliance, and 2) criminal charges leading to fines, imprisonment, or both for individuals violating the Act.
-There are also many others that were dealt with thru binding and nonbinding Public Access Counselor opinions that declared actions illegal, meetings illegal, nullification of certain actions, and declarations that secret ballots are illegal.
As you can see, that although limited information is available thru keyword searches for criminal violations of the Open Meetings Act, there certainly are public officials that have been charged criminally for their violations of the Act. If these cases are publicly available, there must be many more out there that we do not know about.