I have to agree with the other guy on this one.
Unless a player is a complete jerk who is trying to get people killed, it makes complete sense.
ANY thief who is working for the good of the party would immediately tell all of the group of a trap. This just keeps you from having to physically type or say something.
The icon makes MORE sense than an area trap being set off because I type slowly. How does my slow typing play into the idea of immersion. "DM: You run into the trap and set it off killing everyone in your party. If only the thief had taken a typing class."
Just from a role play perspective:
Icon always on:
DM: You enter a new room.
Rogue: I look around what do I see.
DM: You see a crumbling floor/pit fall trap.
Party: DM told us there is a trap so lets wait. (This completely removes the action of what the rogue should do)
Icon not existing: (How it should be)
DM: You enter a new room.
Rogue: I look around what do I see.
DM: You see a crumbling floor/pit fall trap.
Rogue: I take action to warn the party of trap and look for ways to disable.
The rogue/trapper should have to take/use that action just like a healer has to actually use his ability to heal. Passive nonsense hurts the real role play aspect.
Not to mention for a dev team that constantly says they are a small team and can only do so much. This was just such a waste of time for a 17 year old game that already had an effective way to quick type out trap/secret doors. (alias's)