FrogReaver
The most respectful and polite poster ever
That's up to them. Sometimes they may roll a dice to decide. Most base it primarily on the environment you are in with the additional layer of whether their notes reveal anything of significance about your specific location in relation to the foraging.What's the process by which the GM determines the food is there? Do they base on a check?
So if you are in the forest in the summer you find food. If you are in the middle of a barren wasteland you don't (or maybe it's just an exceptionally high check to do so depending on the level of barrenness the DM has in mind).
Now if you are in the forest in summertime and your near something magical causing no food to be around (typcially determined by notes, but possibly via some randomization method).
All of that is up to them. I mentioned above about a fairly typical resolution process.Do they check against their notes? Do they think about if it should be there (make a judgement call)? Do they think about if it makes the game better? Do they have story or plot considerations? What's the real world process?