Savage Wombat
Hero
Yeah; there's a big difference between a campaign premise and a railroad.
For me, it was Paizo's APs that really drove this lesson home:
Handing us a premise at the beginning of the AP? Easy sell.
Handing us a premise at the beginning of the third module? Players feel railroaded, in a bad way.
To which AP or APs are you referring, specifically?