So, I have been playing for several months now, but I have discovered the 3x3mm minimum area for LoS just recently and this changed somehow our games. Today I came to realize a (very weird) consequence of applying this rule and I would like to check with the community to see if this point has already been discussed (I didn't find any topic, but maybe I missed it). In the image above, A pokes out of the corner just enough to see both B and C. Neither B nor C see enough of A silhouette to have the minimum 3x3mm area to declare BS attack, but A clearly sees very well both. After the first movement short skill, both B and C MUST declare ARO or lose it, since A is clearly in both ZoCs. They cannot declare BS attack, since they have not been targeted by A and the exception on page 24 mentions only "the target can draw LoF to its attacker as well". Now, A can leisurely declare BS attack with its second short and go unopposed or, at worst, opposed to a -3 dodge. So, I am well aware this is not as the game flow is intended to happen, I am just pointing out that RAW this is what should happen by applying the rules on the manual and they definitely need to be written differently. This or I am missing something big, that can definitely be the case :P
A sees B and C. If A is in B's facing, B sees A because of reciprocal LoF. If A is in C's facing, C sees A because of reciprocal LoF. Basically, if one of the 2 troopers sees 3x3mm of the other one, both will have LoF to each other.
I know this is how it is played, I am just pointing how that it is a habit and not a rule. Or, at least, not as written on the manual, since LoS is reciprocal ONLY in case of an attack. Then we can all agree everyone plays the intended way, so let's just keep this as a reminder to be written differently in a set of errata or for the next edition. But, anyway, this is one more thing that a player not part of any community that learns to play by himself would, rightfully so, play differently.
Sure, I had not doubt about the correct interpretation and I didn't even think to play the other way. I was mostly pointing to a rule that needed to be corrected in case the issue hadn't been discussed yet. Good to know it had :) I though about looking in the forum but not on the wiki :-\ my bad. Actually, that you know is there any collection of FAQs & Errata somewhere? It would be helpful to have them all gathered together. Or else, I should just probably get more used to refer to the wiki instead of the rules pdf ^^.
And from discussions that I don't care to repeat; in the specific case of checking for reciprocal LOF, you do not care about the units' facing when drawing the comparison LOF. E.g. in the supplied image in the OP, if B and C are in A's back arc, activating C will still give C LOF to A due to reciprocal LOF even if A will not be able to use the LOF to C because drawing normal LOF requires target to be in front arc.
FAQs are released as a PDF in the downloads section of the website and later added to the wiki. https://downloads.corvusbelli.com/infinity/faq/n4-faq-en.pdf