Some clubs use solid walls that are opaque and can’t be seen through at all, other clubs use walls with snow fence or a mesh that is almost invisible, and some clubs use a mix of both wall types. There are a lot of opinions on which is better for durability, ease of setup/tear down, and for stage difficulty, but there are some unique questions that come up when using the mesh walls.
No matter how the wall is constructed, the rules are the same (see 2.2.3 in the Competition Rules). Walls are considered to be solid planes and are hardcover unless declared soft cover in the written stage briefing. And, since walls are solid planes, competitors can only shoot through designated ports in the walls, not through the mesh squares. And if the wall is hardcover, any shots through the wall that strike a cardboard target are scored as misses, and if a steel is knocked down then it’s a range equipment failure and a reshoot (see 9.1.6).
Notice the rules only address shooting through a wall, nothing about looking through a wall. If there is a port in a transparent wall, there is nothing that prevents a shooter from putting their gun through the port and looking through the fence at their optic, sights, or laser (on a PCC). Same goes for a tight shot around the side of a wall. Holding the gun around the corner of a wall and looking through the wall is allowed.
But what if looking through a wall is something that stage designers, match directors, and range officials want to prohibit? One way to solve the problem is to use solid walls when you have ports and have those tight shots around a wall corner. But if the club doesn’t have solid walls, then adding some strips of opaque material around ports and on wall edges is the solution. What can the opaque material be? Coroplast sheets, strips of wood, cardboard from target boxes, and even sponsor banners (but the banners might get damaged, so be careful if the sponsors want their banners back).
If there is nothing to block the shooter’s view through a wall at a shooting position, then they can look through the wall all they want and this includes looking at their sights, optics, and lasers pointed at targets. And there is no rule that prohibits it, only smart stage building can prevent it.