Ok, since the advanced escort Hephaestus skins were made available, I've had to explain this to 5 people in 10 minutes, that it does not GIVE them a ship, it only unlocks more customizable hulls for the advanced escort... that you need to be admiral to even get.
My suggestion is this;
Before ANYONE can purchase a ship costume, a disclaimer pops up stating in big bold letters explaining that they must first have that ship (advanced escort, assault cruiser, etc), the rank requirements of that ship, and that if they have the ship; the "costume" is accessed in the shipyard customizer under the advanced tab.
People are effectively spending real money on these things, and judging by zone chat - they do not understand exactly what it is they bought. Yes, in my opinion the text in the store "(Ship Costume)" should be sufficient explanation - but clearly the concept is not universal.
I had a senior moment and bought the new cruiser skin without even giving consideration to whether or not I had the correct cruiser. My bad, I should have been a more careful consumer; but it would have been nice if they had prodded me to give some thought, or even better - pointed out that none of my characters were currently flying this ship.
Now I will whine - two new skins, and I own the other ship version on both. I'm pretty sure that with my luck, when they decide to release a science ship skin, I will be flying the wrong one of those also.