The comments pretty much addressed this.
No... mods can't view emails either. You successfully isolate yourself from the community when you block your wall. Chat and server become the only link to them then, unless someone else knows their emails.
commented 8 hours ago by Scilicet
That's basically the answer. If a user blocks their wall to avoid mods and ends up getting banned, that's their problem really. We don't really encounter too many issues with this anyway, so it's not something that really needs to be changed.
I think it's better that wall preferences are left to just the user to change, so they can be assured that their personal settings won't be changed by others. It's unlike avatar preferences which can be vulgar or offensive; we need to be able to change those. Seeing emails could be seen as an invasion of privacy, so I think it's best that we're without that ability as well.