Terrain question
I played this layout yesterday and I am confused about a couple things.
Obviously the blue does not block LoS
But the striped dark grey areas. You can't see through it all, obviously, but once someone steps in they can see out and can be seen

Are the light grey walls the only parts of the terrain that block all LoS?
If you are in the terrain and behind those lines, you can't be seen. But if you are not behind those lines then you can be seen?

I ask because I went to a fun doubles tourney a couple weeks ago and the physical buildings completely enclosed the grey stripes meaning there is no way to see units out or in. I then played a game yesterday and we played it like that tourney I went to and it was pretty ridiculous that nothing happened once you walked into a ruin.