Do researchers from some universities not attend top CS conferences anymore because of conflicting open access requirements? From this question and this answer, it seems like the open access policies of institutions like Harvard and University of California conflict with the requirements of the top conferences in computer science.

Can researchers from these institutions really not publish in top CS conferences anymore? How has the change been received, and how has this impacted their careers?
No. The conferences acquiesce to the university policy.

The way it works is that, when the publication agreement is signed, an open access addendum is attached and next to their signature the author writes “my agreement is subject to the attached addendum”. At least that was my experience when coauthoring with Harvard faculty.