The issue with doing something like this is that people HATE being muted. TTT is an RP server, and in muting everyone, you ruin that experience. As soon as you unmute them, they will start screaming once again, not only about the round going on currently but previously in the muted round as well. it just doesn't work.
It gets annoying, i get that. But admins here have all the tools to deal with people constantly spamming the mic. If isolated people are constantly screaming into their mic during game, even if its good information, feel free to mute them, and tell them to knock it off. But dont punish everyone for a few errant people. Yes, there are times when muting everyone is appropriate if a situation is getting out of control, but that should be the only time you do such a thing.
I'm not gonna lie here, I've been mulling around the idea to mute dead people, just to give a little bit of a grace/quiet period. However, on servers that i see this happening, as soon as the fresh round starts, everyone feels the need to speak their mind about the round, and it just makes things that much worse.