In terms of SIS-enriching, there's this need to navigate the spectrum between the following:
A) GM describes every detail of what characters perceive
B) players assume what their characters perceive
Re: resolution mechanics being play priority emphases, y'all seem to be pointing out the same spectrum for processes:
A) in-SIS physics and probabilities determine what happens
B) players assume what happens
Same issue applies. If gathering up all the variables and applying all the laws and rolling all the probabilities didn't take so long, I'd do it! But it does take too long, so sometimes we just assume, and often we strike a balance of common sense + brief look-up + roll a d6, or some such.
So, when do we just assume, when do we go halfway, and when do we do as much modeling as possible? Chris L.'s answer seems to be, "We do less of the 'as it is assumed, so it is' technique when the process matters." And so each game's resolution rules imply what's important in that game, by what they choose to model.
Going back to the issue of simple "what's in my character's environment?", I don't believe rules usually imply such an emphasis (here it matters, here it doesn't), I think degree of player interaction does -- how many questions the GM gets asked, for example. In my experience, "here it matters" is usually "when I fear for my character's survival" (maybe also "when I expect to find clues"?).
Note: it just occurred to me that in order to talk about this, I also need to be able to talk about whether the process of assuming / abducing is actually happening at all at any given moment. A game that facilitates assumptions about the SIS is still probably better than a game that doesn't facilitate thinking baout the SIS at all...
Note 2: if players are making wrong assumptions, better to have those communicated so they can be corrected?