I actually say I believe specifically when I want to convey I may have doubts, usually followed with "please correct me if I'm wrong" but I have worked hard to foster an environment without blaming my team. If there's a need to correct an action after it's been done we correct the action and define it within the process documentation. We've also worked very hard to solidify expectations so that if decisions need to be made without guidance they are clear on the intent of what their actions should be and respond accordingly. It's not a perfect system but it allows us to respond quicker to customer needs without waiting for management decisions.