[Hiddos]

pawn Code:

public OnPlayerConnect(playerid)
{
  for(new i; i < MAX_PLAYERS; i++)
  {
    ShowPlayerNameTagForPlayer(i,playerid,0);
  }
  return 1;
}

public OnPlayerText(playerid,text[])
{
  for(new i; i < MAX_PLAYERS; i++)
  {
    ShowPlayerNameTagForPlayer(i,playerid,1);
  }
  SetTimerEx("ResetNameTag",5000,0,"d",playerid);
  return 1;
}

forward ResetNameTag(playerid);
public ResetNameTag(playerid)
{
  for(new i; i < MAX_PLAYERS; i++)
  {
    ShowPlayerNameTagForPlayer(i,playerid,0);
  }
  return 1;
}

Shows for 5 seconds, then hides it again.