I bet they will do this:
First you have Strength. You pick Swim. Strength forms the basis of your chance to swim. The chance never changes unless your Strength-score does. As you gain levels you get to add capabilities to your skill such as Salmon Swim (You can swim up a waterfall) but the chance to do so is still tied to your Str (some modifiers might apply.)
Or:
If they are really brave they can do this. Pick skills. The skills you pick increase your ability scores. Ability scores is the last thing to be summed up on a character sheet.
They will find you and kill you. Abilities last? BLASPHEMER.
Would be nifty though.