Whenever I do this I inevitably end up with merge conflicts in stuff I absolutely didn't touch. I don't know if it's because it's a monorepo with lots of people committing, or what, but it basically never works cleanly. It's very frustrating, particularly because merging master works without a hitch. So I just do that instead.
Is it really such a huge mess? They'll get a conflict if they try to pull, and then they simply have to rebase their changes onto your new rebased branch, right?