Then we need to fix it.
Seriously, you can't always fight the last guy one by one, especially as in many cases it's a very capable player. And you can't always know it's the last enemy and that he will die the next second, so better block/unload to not Tk someone.
Or do you still want to go without TK punishment? Even without punishment I think it needs to be fixed. I don't want to commit teamkills which are not my fault. And I don't want to be teamkilled by people who did nothing wrong. (I don't want to be teamkilled at all, but ESPECIALLY not from these people
)