Obviously mods are in the right to punish for account sharing. But the thing is... we already had that. Why not just give these users a red nose?
The differentiation of punishment to me implies that logging on to someone else's account "just to do a challenge" is a different magnitude of offense than account sharing for other reasons/multi ownership. In this regard I think splitting hairs only serves to diminish the offenses of account sharers.
Personally I am color blind. I don't care if your nose is white, black, red, orange, green, purple. All the same to me.