Ancient and Darren don't remember what game informs you how to use stairs when you step on them. Just for the record: Hydra Slayer has this, thanks to Ancient, as it was actually his suggestion, and I think he suggested it only because Hydra Slayer uses "g" for "go" instead of ">".
In LambdaRogue, the status line also shows which key you should press to interact with the current tile. Very often, it's just ENTER, based on context (Enter for using stairs, Enter for drinking from wells, Enter for using altars etc.)
I wonder whether there is some cultural difference. I mean, Darren's experiences with showing roguelikes to newcomers are quite different than that of Ancient, Sheep, or me. Also roguelikes seem to be much more popular in Poland than in UK...
In computer science, there's an (unfortunately rather small) research field about cultural differences in the use of software. This not only relates to interface (and obvious things like language, color, writing direction etc.), but also to core concepts of software. Google for Gregory Kersten and his team; they published some good papers about this.
In my PhD thesis, I'm taking on this account and observe people how they use software. Not from this well-known perspective we have in usability tests, but from the view of communication science and sociology (Luhmann). Very exciting topic. Roguelikes are actually one example I'm writing about.