LogFAQs > #950425350

Sorozone posted...

Yeah. I'm not sure when that started being a thing, or the first game where I encountered it, but I do it out of complete habit now even if the game in question doesn't have that level of AI involved.

First time I remember it being important was Splinter Cell 3. They made a point of it in one of the tutorials. MGS2 (and to a lesser extent MGS) had observant guards (footprints, for example), but the doors were automatic so they wouldn't have noticed.