Reason for invisible "Max-Wins" for Key-Fragments?

As stated in the Ask-Riot "There is a bad-luck protection rule that puts a maximum number of wins between key frag drops". I'm asking, why is this number invisible? I mean, one of the goals of this system is to get you to play as much as possible. Wouldn't a "Only 5 more wins for a guaranteed key-fragment" in the post-game-lobby get the people to play more games? Or is there a reason behind it, that I just am not able to think of?