So apparently, later today at 1:30pm ET, we can have the quasi-Ivesian (but probably fairly unedifying) experience of hearing Netrebko's Manon and Dessay's Manon in simultaneous webcasts. "Not that you would, but you could," in the words of the old Nissan commercial. Not that we shall, though we might.
addendum: That 1:30 airtime for Netrebko's Met Manon is @ OE1. Airtime is noon ET most other places.