The trouble is that in closely cooperating teams where I worked, people who did what you suggest ended up in submissive position against people who just do their thing ignoring others. If I proactive think about others and you don't, you get to work however you like it oftentimes making my work more difficult - while I am more restricted and have harder time to make my ideas reality.
I meant team without clear responsibilities and "turfs" supposed to work together :). Clear reasonable responsibilities are an awesome thing and kill whole bunch of insecurities and resulting behavior.
in a professional context requiring collaboration, that's an asshole move, and people who do that sort of thing on a regular basis should be reprimanded.
