I forget where I read it, but it was a sci-fi conceit that many of the red giants are actually much brighter stars seen through dyson spheres. I guess you could say the same for red dwarfs, that they are even more common than we think, and explain all the theorized extra mass the the universe is supposed to have by saying it is in red dwarf dyson spheres that we can’t see.
Freegards
Heh... or maybe they’re just big “Open” signs for some kind of space biz.