Not to pick a nit, but is "embargo" really an accurate term in this situation? i've been on the issuing and receiving end of hundreds if not thousands of embargoed press releases in my career (unrelated to theater) -- they always involve the dissemination of confidential information prior to the time the issuer wishes it made public.
there's nothing confidential about a show 2,000 people see eight times a week. the producers certainly have made known their views about "early" reviews, but i don't think they've embargoed anything.
OK, yeah -- that's a nit ...
:)
"You, sir, are a moron." (PlayItAgain)