This, in of itself, is a finding. The researchers will justify their research with "we were banned which is a possible outcome of this kind of research..." I find this disingenuous. When a community of open source contributors is partially built on trust, then violators can and will be banned.
The researchers should have approached the maintainers got get buy in, and setup a methodology where a maintainer would not interfere until a code merge was immanent, and just play referee in the mean time.
I don’t mind them publishing that result, as long as they make it clear that everyone from the university was banned, even people not affiliated with their research group. Of course anyone can get around that ban just by using a private email address (and the prior paper from the same research group started out using random gmail accounts rather than @umn.edu accounts), but making this point will hopefully prevent anyone from trying the same bad ideas.
The researchers should have approached the maintainers got get buy in, and setup a methodology where a maintainer would not interfere until a code merge was immanent, and just play referee in the mean time.