Next time you want me to share some info, just send a pm cuz I don't read all themes on the forum, but I do believe in equality.
I do understand your concern and first felt the same way probably: can't beat them, join them.
It gives you huge advantage in my opinion and should be technically impossible to use [the only real way to restrict it] ether publicly accessible.
Wall replacer mod greatly breaks the atmosphere, look and overall experience. In additional it's not full, as server has huge amount of custom graphics. Basically game masters use this thing too, as they can't apply mouse commands on people behind walls / roofs. I don't know if it's same for this server or not.
Going further, there's
item highlighter. It paints green contours to some items, not all again. It makes them highly visible in opposite to custom models. And they look ugly.
Installation: put the archive to the data directory. Edit DataFiles.cfg in the game folder to add a path to the file. There're several examples inside.
If you don't care about domination or/and can enjoy the game the way it is, I don't recommend to use it, but if you'll do, you will find stuff you'd never find otherwise and will be able to understand the building structure without entering it.
I believe there's should be possibility to turn on / turn off walls and roofs from the client or technical impossibility to use such modes... but if you don't use it now, you lose.
And as I make something for you, please do something for me too. Stop spamming useless and untrue messages like "Hello wallhacks." on the forum.