Background:
The LOS mechanics include drawing a line from the centre of the 'looking' figure's space to the centre of the 'target' space. Any obstruction that this line passes through blocks LOS.
Many people argue that there is no preclusion for obstructions in the target space (or the originating space). They therefore claim that, for example, a hero cannot shoot a razorwing as it passes through a rubble space - the rubble blocks LOS to the razorwing! The holes in this logic are painfully clear, but the thought still comes up regularly enough to possibly deserve a clarification.
Clearly, neither obstructions in the originating space nor in the target space block LOS, or, as a single example, tree spaces would make all figures in them both invulnerable and unable to attack.
This could be clarified with a simple statement.
"When checking LOS, the line is drawn from centre of space to centre of space as on pg9. However blockages in either the originating space or the target space do not block LOS. Only blockages between those spaces (including walls, closed doors, other figures, blocking obstacles and blocking props or terrain) actually block LOS from space to space."
If necessary, this could be turned into a question. Something like...
"How do I measure Line of Sight if either the attacker or the target are in spaces with obstructions that block Line of Sight?