How is such a ban going to be effective? The "researchers" could easily continue their experiments using different credentials, right?
Arbitrary anonymous submissions don't go into the kernel in general. The point[1] behind the Signed-off-by line is to associate a physical human being with real contact information with the change. One of the reason this worked is likely that submissions from large US research universities get a "presumptive good faith" pass. A small company in the PRC, for an example, might see more intensive review. But given the h…
In late January I submitted a patch with no prior contributions, and it was pushed to drm-misc-next within an hour. It's now filtered it's way through drm-next and will likely land in 5.13.