Re Encores shows - I've always thought of these four-to-five performance Encores presentations as "events" rather than real revivals. These are sometimes casts you couldn't get together for a regular run. While I myself didn't actually scream and holler at the Encores Follies performance I saw, I totally understood about the audience feeling they were at a special event of sorts rather than at a revival, because of the nature of the presentation (only 5 performances, extended to 6 by insane popular demand).
(This differs greatly from the summer Encores shows, which are revivals in several-week runs.)