Depends on how far ahead they are and how many fill-ins are ready to go.
Batwoman, for example, really has no excuse for being late for awhile given that it's been delayed three times at this point. And I'm sure there are drawers full of unused Batman and Superman stories that can be used in a pinch. (Apparently Kurt Busiek's Krypto story finally saw print recently; I'll have to pick that up.)
Now, books getting canceled at the drop of a hat due to low sales is probably the most potentially alarming thing about all this; Blue Beetle's been canceled once and it could easily happen again. OTOH, there are books DC's going to want to prop up for various reasons -- Jonah Hex has been in print for years despite low sales and an atrocious movie tie-in, because it's DC's only western. (That's why, while I think Ted's right that Demon could face immediate and arbitrary cancellation, I think they'll keep the western and war comics around as long as they can just for the sake of variety.) Similarly, Batwoman, Static, Blue Beetle, Firestorm, and Mr. Terrific all feature minority characters, which is something DC's trying to play up right now. (Course, I AM cynical enough to believe someone could say "Well, we only need ONE black guy" and cancel Firestorm and Mr. Terrific but leave Static.)
Still, though, books I like being canceled prematurely (Thor: Mighty Avenger) or retooled so I'm no longer interested in them (Cornell's Action Comics) aren't exactly a new phenomenon.