About Perception/Matrix Perception:
1. "Obvious" things - do you need a test to see a large AR advertisement in a mall or find your own pants lying in the middle of the empty room? I think you don't. They are
obvious. BUT if you are running from corpsec at the mall or trying to find these fraggin' pants under a suppressive fire, it's possible to miss even so obvious things - so GM may decide that you need to make a simple test to see them.
2. Perception in Matrix - if you are inside a node, you see other icons. And they probably are often shaped in some standard way - you know if you see a working Winamp, or Windows, or Linux etc.
BUT if you are entering a node node unknown to you, shaped in the form of fantasy castle, you are not sure what is what. Paydata could be shaped like books in wizard's library (in a corp's node, where wage slaves need aneasy way tofind what they need), or a flying faeries, or a goblins' poo (you know: hackers and their sense of humor...). The knight at the door may be a source of newsletter, another hacker, IC with Analyze Program only, or a deadly Black IC armed with rating 8 Black Hammer. You see it, but you can't be sure what they really are - so you need a Matrix Perception test to know.
QUOTE
SR4 p. 217 (emphasis mine)
If you wish to specifically examine an arrow, dot, or other
Matrix object—users, programs, IC, nodes, files, etc.—take a
Simple Action to Observe in Detail (p. 136). Make a Matrix
Perception test using your Computer + Analyze program
Looks like you automaticallygain some basic data about icon that you are looking at - i don't think that wage slaves working in a node must Analyze EVERY SINGLE icon before using it - but need a test to learn anything more. Good idea, sometimes - everything in node can be disguised as a something else, use Stealth etc.
Besides:
QUOTE
SR4 p. 217-218
When you are accessing a node, you may set your Analyze
program to automatically scan and detect other users/icons on
that node with a Simple Action. A successful scan will be reported
to you. The program will maintain that task for as long
as you are on that node or until you kill that process. The gamemaster
secretly conducts Matrix Perception Tests to determine
if you detect other icons accessing the system.
(I'll check SR4A, of course, but I think these rules remain unchanged)