Saturday october 8...
We had our first event at www.lfs-lemans.com

After about 6 hours, all players lost sound...
Offcause it where fixed by shift+W...
But is this a known problem ?

I've known this problem since S1. It doesn't really matter if you're playing (online, offline) or not. It also happens when LFS is running idle in the background for several hours. I haven't measured exactly how long it took for it to happen, but ~6 hours seems to confirm my experiences quite well.