Not related except by brown, surely?

The Brownies wear brown uniforms and collect brownie points for their good deeds.

Brown nosing is the unstated obvious; Private Eye perhaps made it more prominent with their award of the OBN (Order of the Brown Nose).

It wouldn't have occurred to me to connect the two, but now that you've done so I'm afraid the image will never leave my mind. Those poor Brownies. :)