Intervention is necessary

A while back Emily asked if there wasn't a time when a teacher was permitted to intervene in a student's writing life. I'm beginning to think that intervention is necessary if student writing is to become meaningful. I'm not talking about directing here but about questioning that broadens the student's horizons about what could be, deepeing the student's concept so that s/he doesn't see things as black and white but as gray and negotiable. I'm wondering though why Coogan thinks that e-mail is better suited to this kind of questioning. Couldn't the writing center extend this conversation at the point of need as well?