Herd Behavior.
Whether your mate is doing this purposely or not, this method is often used to elicit the frequently observed behavior in humans to follow others lead when supporting ideas.
We see this all to often in voting.
Often people who preface statement in the manner you have suggested are doing so in an effort to have you agree with whatever idea it is they are presenting and bypass normal tendencies to contemplate on an idea. It is used as a manipulative too to control i.e. answer the way I want you to and don't "rock the boat".