Interesting point. My actual line manager actually rarely gives me any direct instruction. I would say our team has no hierarchy of 'command' as such and really does not need it. We simply discuss what needs doing (i.e client requirements) with whoever seems most qualified and do our best to get it done. It's flat as you like and I think the arrangement suits most devs - we all know we need to make money to survive and what we need to do to achieve that.