I checked over the rules of the CR again, and no where did I find that copying a “members” screenname is deemed to get blocked. The only thing I did see was, that it is against the rules to mimic a moderators name. So after all PBA must be a mod, and one may not mimic his name.
Or maybe, the rules say “Opinions are okay, but demeaning Torah, halacha and gedolim is not okay.” So maybe imitating a gadol is demeaning him?