Stag Lord said:
Potentially immediately, considering that with FoW gone, you are free to play a Lord or Lady in the same Marshaling that you played Margaery and trigger the Responses on the Entourages you just chucked.
My own earlier point, which goes along with Stag's here, was that even if you don't use Margaery to have them replace FoW with RBD during Marshaling of Round 1, they're probably going to use that same RBD during Plot of Round 2. Either way, you're losing the same 4 cards, right? So why is Margaery-into-RBD-Round 1 supposed to be so much more devastating than waiting until the plot phase of Round 2 to get hosed by RBD in exactly the same way? You aren't losing anything by using Margaery, and depending on the 4 cards you keep - that you can now use! - after the RBD replaces the FoW, you could end up gaining quite a bit.