Good on Volquez for rightly pointing out that it's logistically impossible. Not to mention, no self-respecting major leaguer is going to rely on stolen signs to determine which pitch to swing at. I don't hear Alex Rios chiming in saying, "Yeah, we stole signs when I was there, the team management encourags it."
Even if you were stealing signs, you would never rely on them being 100% accurate. Furthermore, if you are getting your signs stolen, that's completely on you.