As nobody else answered the question, but went on to give opinions about other things, of course when she answered "no" it sealed their fate, how can you even wonder?
Obviously there are way more deeper issues and questions and this movie is not about answering questions and nor should it be. It's left to be open to interpretation and I like movies like that
But yes as hokey as it may sound, every time Sally would ask Vika (and keep in mind she only asked Vika, never Jack if I remember) Vika would always answer yes. To answer no was basically like hitting the self distruct mechanism in which the drone would wipe them out and another "mop up crew" would take over.
We can only assume there has been some 50+ stations given their number, either scattered about the globe or built / setup once upon a time, maybe hidden from each other within false radioactivity zones, one can only guess. But who / what built the platform stations in the first place, the Soldier Jacks? Certainly the drones couldn't. Did the water siphoning devices also come out of the Tet? Is the Tet 100% automated and non organic, hence the need & only reason for the abduction & cloning of the Jacks & Vika's? Some of this seems pretty clear but again a lot of it is open to interpretation or possibly left that way for a possible prequel or sequel. Part of me hopes so but another part of me doesn't as this movie is great and stands well on it's own. It would be a shame to see it go down like the Alien or predator movies where they just didn't know when to stop and call it quits...