No need to actually restrict the content as such, it's more a "marshalling"
thing, determining what sort of content can go where so that it can be handled
cross-client effectively. If you tell management (or any client group) that
they can have jes' 'bout anything they want in both environments without losing
content, they will probably be more amenable to separating the content into
separate RTL fields. You're not taking anything away from them; you're just
ensuring that content created in the Notes client will not be damaged by
editing on the web. It's worth fighting for, IMHO.