Different? - I don't think so

The first thing you (creative "person") will say to a new client is: "I think different". Yes I know you see other agencies, but we really do think different, plus of course, we'll be cheaper and you will be our main client (and more bullshit), but first of all, different. Do you really (I say you because, I know I do) mean that? Because I am puzzled. People, explain to me how come two ad agencies, both Israeli, Both represent a large beverage company (both think different, not) come out with an almost the same campaign slogan?
Of course I am talking about SCHWEPPES (drink different) on one hand and SKOL (it's different) on the other. I bet you the client is thinking something different now, a different agency maybe? well if he is not he deserves it