When we were kicking around possible titles for The Economics Anti-Textbook and I suggested that title to a friend of mine who teaches in what might be called a high-powered place, he warned me that someone (particularly someone without tenure) "would get in trouble" there if the powers-that-be found out he/she had used a book with that title in class. Fear of such trouble can keep any potentially dissident faculty members in line.
I've never faced such problems myself, working in a small provincial university in a quiet backwater of the country where the local plutocrats reign almost unchallenged. No one cares very much about what I say in the classroom or what I write.
But ideological control in the large institutions that matter, particularly the ones that train graduate students, is much stricter. I'm reminded of Noam Chomsky's explanation of why ideological control is much more severe in the big centres -- New York, Washington, Los Angeles, and so on -- than it is in small towns, where things can appear in the local paper that would never be allowed in the Washington Post or the New York Times. What's printed in The Topeka Capital-Journal in Topeka, Kansas, just doesn't matter a whole lot.
What's happened at Notre Dame University in the US in the last few years is an unfortunate example of how non-orthodox views get sidelined and eliminated. For those who don't know the story, the economics department was spit up in 2004 (as described here) into the orthodox group and the non-orthodox. Last year, the university bosses slated the non-orthodox department for demolition, as described here in the Chronicle of Higher Education.