[nilmind]

Exactly.

To everyone who said that sight reading is when you read something for the first time, that's much more true when it comes to reading real music. But what happens is that unlike Bemani, playing real music over and over again makes one tend to memorize the song. The fact of the matter is that in music games, we're just all trained to sight read so well while memorizing pretty much never happens (except for memorizing rhythms and where harder sections are, which is really what makes playing a song again a bit easier; we sure as hell don't memorize the notes though). Therefore, we're pretty much sight reading notes all the time, so the term "sight reading" is actually misused a lot in these games.

However, although technically incorrect, I believe that when people say "sight reading" in these games, they DO mean reading the song for the first time, so that's the real genuine answer.