A man was recently convicted in Madison of planning a terrorist attack
on the University of Wisconsin Madison campus using the underground steam tunnel network. Police found bomb making supplies and guides in his apartment along with a map of the campus steam tunnel network with various locations marked on it.
Though he was arrested last February, this case hasn't gained widespread attention until now, so the UW Madison steam tunnels may be too heavily watched for the next month or two at least, and other universities in the midwest may follow suite under public pressure. If you plan to run steam tunnels any time soon, just be aware that security may grow tighter and penalties harsher for at least a little while.