I was playing earlier today and was stopped by a few defenders blocks for which the character with the block was literally on the other side of a wall. It just didn't make any sense that a player could block an attack for an ally when they where pretty much staring at a wall the whole time. The same general issue comes up with cause fumble tho not as many people seem to use it more than likely because it is limited to melee and does not draw a card when triggered. As far as the restriction to Line of Sight I personally think that either should trigger if the character with the block can sight either the attacker or the character being attacked. I just feels a bit wrong having it a card that omnisciently triggers through walls.