Not related to the blog's particular topic, but given my son is big into the
SCP stuff, it was interesting to see the blogger has analysed some of those critters for use in games.
I thought the descriptions of the punishments were hilarious: "Now we all know this is a serious railroading crime for which the GM must be punished by no fewer than 10,000 words being written about them on OSR blogs over no fewer than three months." Comedy gold!
The question for you dear judge - which "railroading" crimes are the most heinous? And which ones are mere infractions, maybe worth a simple fixit ticket
I'm on record suggesting that railroading is more about DM/GM/referee motivations, attitude, and overall conduct, as opposed to any specific in-game declaration of goings-on, so I'd be inclined to say that all the examples are basically innocuous - or at least, that there is insufficient information to say that railroading as a pattern of GM conduct is happening.
For scenario I, question (A), I'd actually go somewhere between 2 and 3 for an answer - if I were GMing that scenario, instead of announcing the player characters are now at the mansion, I'd prompt the players with something like, "it seems you're getting frustrated at the apparent lack of progress, did you want to go ahead and get to the mansion proper?" This also means that if the players are actually having a good time and are roleplaying their characters' frustrations, that will be made clear.
For scenario III, I would say that if the game system expects the GM to make sure the player characters have enough information to keep the game moving, it's a neglect of their duties as GM according to that system's expectations (and genre tropes), but not railroading. So answer 2, but without exonerating the GM of an error.