I said something like this on a TTT server around the time you posted this. Were you on the TDR 12 slot server last week?
I consider it a positive that after you die you do not necessarily know who is a traitor yet, so one of the things you can do as spectator is attempting to figure that out.
This is true and so is the ghosting problem that was mentioned, but how about you give just the traitors this ability? It would make one's job as a traitor easier by notifying them of deaths exactly when they happen. The traitors already know who the other traitors are and they can already see the "Missing in Action" list, so it's not like there would be anything negative.