Celebrim
Legend
Thinking about it more, Schrodinger's Map can also be unmasked when a DM is playing favorites. (This isn't quite "railroading" in the traditional sense).
Typically this would be the case where the DM's "favorites" always gets an easy walk every single time. On the other side of the coin for players the DM really doesn't like, the DM will consistently make things really miserable for such players.
EDIT: Essentially it is like the DM trying to railroad certain players they don't like, straight out of the game.
The way to summarize it is: softballs for the DM's favorites, and extreme hardballs for the players the DM doesn't like.
This most often is seen when the DM is winging it, and can happen unconsciously whenever a DM is winging things without prep that usually require prep - such as a map.
Schrodinger's Map, when implemented as part of a plan, is generally as fair as a linear dungeon/environment of the same construction would be. You just simply remove the false choices from the environment so that the true linearity is on display.
But when winging it, yeah, who knows. That's why I consider it almost impossible to avoid railroading the players when you wing it. Winging it almost gaurantees Schrodinger's Map by definition, because nothing gets on the map until the circumstances leading to its need have just occurred. Even worse, I've seen 'Winging It' lead to numerous instances of 'Schrodinger's Trap' where a trap exists because the group searched for it but does not exist otherwise (observable by observing two different play groups pass through what was ostencibly the same dungeon), which in further leads to the problem that now that you've started the DM thinking about traps you have to continue searching for them because now they'll come to existance because you didn't search for them. Conversely, I've seen 'Schrodinger's Ambush' occur from winging it as well, usually as a result of the DM consciously and unconsciously tailoring the obstacles to the immediate events and abilities used by the players.
Seriously, while railroading is usually associated with DMs trying to keep their carefully laid plans for derailing, if you'll look over the above list you'll realize that it requires an almost inhumanly unbiased DM to successfully wing it without using these techniques. A world that is being created entirely on the fly without prior sandbox prep is almost inherently a Tiny World (no where exists unless it is visited), Shrodinger's Map, filled with Hand Waves, Endurium (in the form of fiat decisions being made based on circumstance), False Choices, and Schrodinger's Stat Blocks no matter how hard you are trying to be fair.
If you have a carefuly crafted plot, you might be a railroad conductor. But if you have no plot and are just making things up in response to player actions, then you are a railroad conductor (and the first time you get in a situation where there is a 'control group' to test it, it will become really obvious).