The first of these concerns Individuals, Line of Sight and Cover.
The actual rule - conveniently under "Individuals" - states:
“Individuals never block line of sight or offer cover against ranged attacks.”
Unfortunately Apu's Brave Act Was To No Avail!
I find that in a lot of games that people are not aware of this rule or they play it wrong. My guess is that while an Individual is effectively "invisible" for LOS or Ranged Attacks, it is "material" for movement, charge path etc.
You commonly see people spending a lot of their time positioning Individuals so they are not intervening between a unit (often another Individual) and its target for a Ranged Attack. Under the rules this is not necessary.