I also have this on my server, Not that it matters because its always been like that as far as i remember, You get the odd 1 complain about it but its not really a problem, I just throw a nade thru a window before i try to snipe etc, You can kill people thru the window as long as the glass is smashed first
Yes you are able to kill people once the glass is broken.
The problem mostly lies in the Sniper Only servers. I only play SO and during a SO war it's a huge setback (time consuming, act of surprise gone etc.).
(You also do not have pistols and nades in SO wars.)