I think that communication and the ability to find things are one of the greatest challenges on this platform. On the platform it is only possible to write warning etc. in a post and that is not a good way to communicate. Cheetah is already in the commentfield and as there is no privacy on Steemit it is always possible to check all the actions the user has done and all the flags he/she has.

I am still rather dubious about a centralised warning - steemcleaners are not an official channel, just some users that has made their own vigilante organisation (consisting of fine people by the way).