You seriously want to spend your time playing walking back and forth and being a liability to your team?
You really have a serious problem with engineers don't you?
"liability", fine, maybe we don't get many kills, or any at all. But there are plenty of noobs out there that do nothing aswell. The "cannon fodder" excuse does not work either as the enemy team will always try to come over the the construction site and destroy ir, thus distracting them like a noob would.
Stop being so hateful towards engineers, people have the right to play the game however they want to.