After reading the discussion on this, I think I see the misunderstanding. The breakdown is between a "Rule for Ownership" and a "Method of Aquistion".
Rule of Ownship - "You must be this tall to ride the ride. No exceptions"
Method of Aquistion - "This is the line you go through to ride the ride for free."
For instance, the Bismark is a tech tree ship available for free in game. You need to Research the precedeing tiers in her tech tree line before you can purchase her for Earned Ship XP and Credits. This is her free-to-play Method of Acquistion and is the only way to acquire her as a routine standard.
The Bismark could be featured in an event, or linked to a bonus code, or sold directly in the premium shop/armory. These would not be her normal method of acquistion, so they would stand out. However, there is no Rule regarding use of the Bismark outside of having an internet connection to play the game.
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The free-to-play Method for Acquistion of a SuperShip is to own 3 Tier Tens and have researched the prior ship in the line so you can purchase her for Earned XP and Credits.
The SuperShip could be featured in an event, or linked to a bonus code, or sold directly in the premium shop/armory. These would not be the normal method of acquistion, so they would stand out. However, there is no Rule regarding use of the SuperShip outside of having an internet connection to play the game.