I'm guessing they're quickly blocking then unblocking people who follow. That's the easiest (only?) way to remove a follower. I do this when I want someone to

I'm guessing they're quickly blocking then unblocking people who follow. That's the easiest (only?) way to remove a follower. I do this when I want someone to stop following me but I might still want to follow them or I don't want them realizing/caring they're not following me anymore or feel I'm blocking them entirely.