if you were travelling at a safe distance you would realise they were slowing down
i followed a car through geelong during peak hour... it had no brake lights at all (VP commodore, chick driver, clear tails, stockies on the back loser)
If i were to leave the 2 car 'safe' gap other cars would have continued to get in front of me, hell even one car length and cars start to push on in. In which case i would have never got anywhere.
Not sure if you know geelong at all but traffic through there is a bitch, you need to be half watching the car in front, half watching the traffic lights ahead, making sure the truck beside you in the stupidly tight lanes doesnt crush you, while you operate your own car.
It is as nasty as it sounds.
Just saying, there are always other situations to consider.
and no, i don't yet know how to multiquote.