chess world champion won't be here for sure, but i know some times one ex-worldchamp will do it , his name is well known. Kaspraov, some thing like this, i can spell his name exactly.

a world champion no need to use computer when playing on line. he could win every game very easily.
but if a world champion using computer to play in the championship match and his opponent did not know, no one could take his title away, he can keep it forever.

today even in the very high level chess, such as the world championship match, the player is still complainng about computer cheating. have you heard about the "toiletgate"?

online rating is not a true rating, a 1400 could be a 2000+, a 2400 may be a 1600, who knows?