[blindluke]

> and so one can guess what correct fingering would be when there is no teacher around

At least in some cases, yes. For me, that's the real point of having a teacher - learning the thought process, not the pieces.

One thing worth mentioning is that sometimes the correct fingering for a piece is contextualized. There are pieces that you might treat as a goal in their own right, but they might also be just a stepping stone to other pieces. For example, you might see a sequence of three notes in the left hand, and there will be a "correct" fingering that's most comfortable for just those three notes. But the teacher that suggested this piece knows that those three notes can be seen as a simplified version of a six note pattern that occurs throughout a more difficult piece you will tackle later. So the "correct" fingering they suggest to you is the fingering that's most comfortable for the more difficult version you haven't played yet. You're not looking at the piece as-is, you're thinking of it in the context of what you'll eventually play and optimizing the fingering for performance of the target piece.

You will often hear that "correct" fingering is the one most comfortable. This is only partially true when you're in the early stages. Often, you go for something that's suboptimal in a particular piece because it will be more comfortable in another piece down the road.