the most users who chat only in their few channels have no problem with mirc 7, because the parser understands privmsgs sent in iso-charset. So the user can read the normal special characters like é or ü.
But opers or admins like me must have the possibility to join every channel existing in their networks. We are not in the position to ban users that cannot use unicode.
But if they use clients with iso-charset, we cannot use mirc 7 that acts completly inconsistent with existing servers.