It's tricky, because your character might have a good reason to go in an area where the dm doesn't have anything prepared. I've often had a dm instinctually put up form of guardrails when players veer beyond the scope of their plan, and conversely, as a player you might have to guess what the prepared material is so you can go in that direction.I should have also included in my first comment, that it is generally the adversarial players who throw around the railroading accusations. They are the ones who want to just do whatever they feel like and not engage in the social contract that is playing in a cooperative game.