[boxfire]

TTY queries are written to stdout but read from stdin. That's not user interaction. E.g. if you're system doesn't have ioctl for window size (or you're over a remote serial etc), setting the cursor to the bottom right and asking it's position. Those programs break with no stdin because a tty is inherently bidirectional communication!

[JoshTriplett]

Such queries are not universally supported, and a program using them has to be prepared to expect a lack of response to the query. (This is one of many issues with such queries.)